2)

Australia
The test runners-up are going through kind of a transition period and it will be interesting to see how theirs turns out.
Tests
Tests could also be reasoned as Australia's best format, but it's tough since they are good at everything. But it's certainly their biggest priority, and one that is transitioning right now.
1.

Usman Khawaja - This is the only format he plays now and although under a considerable rut of form, we have 45 players to fill and thus he is more than good enough to be in the Test team. He adds seniority and experience to the opening pair as well in a period of transition
2.

Sam Konstas - The more exciting but less experienced half of this opening pair. Konstas has shown potential across formats domestically but has only kicked off in Tests for Australia, and as the next in-line opener he finds his place here. So more or less the regular opening pair.
3.

Nathan McSweeney - Just like for SA, we have a rookie at the 3 spot. With Marnus dropped from Tests and Australia yet to find a good enough No. 3 replacement, we shoe in McSweeney here who, though has been decent across formats domestically, has again excelled mainly in and made his international debut only in red-ball. But he will not open, fortunately.
4.

Steve Smith - The man who carries this lineup, and with retirement in ODIs, it's a no-brainer he makes this team but let's be honest, even without it he is. Tests are his best format by miles and he is the best of the test format too.
5.

Cameron Green - A toss up between him and Head, but ultimately Green has proved more in red-ball cricket, and with Head's recent rut of scores in Tests compared to LOIs, this decision was easier to make. At his comfortable spot at 5, he is a far better player than he has shown recently.
6.

Beau Webster - This spot was easy to fill, Webster has only played tests and gotten off to a great start as well, so there's evidently no challenge from any of the other formats. He's also the regular No. 6 now.
7.

Alex Carey - I would not say Carey's best format is test cricket, but it's ideal to go with the regular keeper who's also the superior glovesman. Only Inglis was there as another option anyway, and he's surely better off in white-ball.
8.

Pat Cummins

- The regular skipper will lead the test team as usual as it is his by truckloads his best format; even if we don't prioritise tests to have the best attack, Cummins would walk into tests first- he is far superior in this than white-ball, and this is where he is actually quite world class.
9.

Nathan Lyon - Lyon is the frontline Test spinner and doesn't play other formats, so it is another regular spot that gets filled without any debate.
10.

Josh Hazlewood - Hazlewood is quite the all-format fast bowler, but he has always been best at tests, in my opinion, as it has been the format he has been excellent at for longest, and we try to retain as much of the full-strength attack as possible, and I rate him over Starc. And we have enough depth for other format attacks.
11.

Scott Boland - At least in this universe, ScoBo finally gets his nod into the XI, as I decide to sacrifice Starc who I do feel isn't the best at tests over all formats. And I only could do this easily because Boland is just so good and the attack feels just as strong thanks to his quality. Would be harsh if even here he had to be benched as he doesn't play LOIs either.
12.

Marcus Harris - Backup bat, the only one who's been around the test side as long and doesn't crack other teams. Let's hope the others play well enough though.
13.

Michael Neser - I do rate Neser in other formats but he hasn't played for Australia much there, and in tests he has been great- but sadly he has to be the backup quick as Boland is just better, but he has got a better shot of playing here.
14.

Fergus O'Neill - Not someone from Australia's set-up, but he has just been so good in FC Cricket that I wanted to include him in the 45, helps have other options for LOIs too.
15.

Todd Murphy - Ultimately Lyon's successor as the off-break bowler, and as a test specialist gets the strategic nod over Kuhnemann.
Just like South Africa, we have managed to snag most of the core back. The No. 3 is inexperienced but even full-strength Australia is struggling for that atm, and only Head is a proper miss. Boland does the job well enough to ensure this is a full-strength attack too.
ODIs
Australia are the current World Champions in the format, but have lost three big names to retirements recently. So what will be their best team with what we have left??
1.

Travis Head - omitting him from the Test side is precisely for strengthening this ODI lineup, with Head at the top like the full-strength one. I would also argue this is his best format, so not much of a tough call to make.
2.

Mitchell Marsh

- Marsh is definitely amazing at T20Is, but with the amount of depth we have for the shortest format compared to this (remember the retired ODI players still play T20Is), it was better to have him here. He's almost equally good at both formats of late anyway. Now we have managed to retain the full-strength ODI opening pair too, which is brilliant.
3.

Matt Renshaw - At no. 3 here we have another gamble but Renshaw has been in top form in the List A competition that he HAD to be in this side. McSweeney being in the Test outfit contributed to this too, and I feel though they could be swapped, Renners' 50 over form needs to be given the weightage.
4.

Marnus Labuschagne - Dropped from the tests, Marnus makes his way into the 50-over side, actually a great thing for the ODI team to have more experience. He's been much better in ODIs of late, after making a comeback into the side in the World Cup. Fits properly at 4 here.
5.

Peter Handscomb - Might be a bit of a bias from me here- but I rate Handscomb in ODIs, the 2019 nostalgia is a big reason, but he was very very good if I remember, and I think he is the best option for a keeper who can bat in the middle-order with Inglis left out for the shortest format.
6.

Cooper Connolly - He is a very promising talent and though there isn't much to differentiate his claim to be in either of the white-ball sides, I am again considering the balance and throwing him here- because likely he'd be benched in the T20I side based on who we have. He has a composed batting mindset which I do think is better suited for ODIs anyway, and he has a future in the format. + the second spin option.
7.

Aaron Hardie - I definitely consider him a T20 player more but for the sake of balance we have him here. The skill difference isn't huge, he's played ODIs too so it isn't much of a big deal when he is yet to prove much in either format. Provides the Pace AR option that Australia usually have in their XIs.
8.

Mitchell Starc - ODIs still have to be Starc's best format after all these years, even above tests. With how good Boland is, it gives us flexibility to play Starc in this team, adding some solid experience, and also because I do truly believe it his where he is best.
9.

Xavier Bartlett - Bartlett had an insane start to his ODI career and just didn't play again, but 8 wickets in 2 games is quite the way to kick it off. He should be among the top choices for the next in-line quicks in both formats but I believe he is better suited in this side than the T20I one.
10.

Jhye Richardson - Richardson if he is actually fit is a gun across formats, but the test attack is pretty much occupied and he's far too good for the Bench there; and he hasn't particularly impressed in T20Is. However he has very promising ODI stats and was very good when he actually played the format, so I think this is his best format so far.
11.

Adam Zampa - Zampa is the lead spinner in both white-ball formats, but arguably deserves to be in this side for two reasons. 1. He is ultimately better in ODIs, 2. The T20Is have more spin depth to afford having him elsewhere, compared to ODIs. Him and Starc make sure we have retained half of the full-strength attack anyway.
12.

Josh Philippe - The backup bat + wk, felt Handscomb is better at No. 5 so he was preferred ahead, but Philippe is quite good too. It was between him or McDermott.
13.

Will Sutherland - He played a few ODIs recently and is pretty good across formats domestically, but based on his international experience I'll have him as my backup all-rounder here.
14.

Lance Morris - Morris is exciting and probably better in red-ball cricket but he has shown he can do well in LOIs too and has made his ODI debut as well. With enough pacers in the test side, he finds himself here.
15.

Matt Kuhnemann - Picking Murphy as the test backup spinner means Kuhnemann can fill the void in ODIs. Well unlike Murphy he has actually played ODIs and done surprisingly well in his short career, so it would obviously be better for balance to keep him here.
The ODI side is certainly not full-strength but considering recent retirements, it might not be far off. The openers are perfect; the bowling lacks two important quicks of course but I feel X and Jhye are very good replacements. Most of these guys will play ODIs in the upcoming run to the WC anyway, I believe.
T20Is
Finally we move to the T20Is, with the remaining crop of players. A few players being T20I specialists will help us here, but let's see what we have.
1.

Mitchell Owen - Owen had a crazy BBL and is currently lighting up the MLC, and has gotten his maiden T20I call-up too. So it's a no-brainer that if he has to play in some format it is here, as he is also making a strong case for the future T20I opener.
2.

Matthew Short - Short has had experience across both white-ball formats and not proved much in either, but I ultimately feel he is better off in T20Is. He has had some crazy BBL seasons on pitches that "suit" him, and also with no top-order spots in the ODI side, it was easier moving Hardie/Cooper there to accommodate him here.
3.

Jake Fraser-McGurk - McGurk has been a bit of a failure internationally but is currently doing well in MLC; based on our options he is a decent choice for the No.3 spot here, which I feel he is better suited to than opening. This is the one format I do have hope in him based on his play-style anyway, keep him out of the ODIs.
4.

Glenn Maxwell

- A massive boost to this young and raw T20I side is Maxwell, who will also be the captain. Even usually I would have no doubts about going for him in the T20I team as it easily his best format, but the guy has retired from ODIs anyway, so this is literally a no-brainer.
5.

Josh Inglis - Inglis has performed across formats for Australia now and would be a good addition to any format but T20Is I still believe is his forte, the one where he has proven the most, and the one which gave him life in the Australian Team. Thanks to Pete in the ODI side, I think I can go with him in his best format.
6.

Marcus Stoinis - Stoinis is another experienced campaigner adding power to this team, and just like Maxi, he also retired from ODIs making this a no-brainer call. And even more so like Maxi, this is his best format, and less so like Maxi, this is his only actually good format, so it was gonna be the same decision anyway.
7.

Tim David - A proper T20I specialist who doesn't even play ODIs, David is one of a kind but that makes it an easy call to have him as one of the first names in this team, and with Maxi and Stoinis we get to retain the bulk of the full-strength middle-order, with our specialist finisher at his best here at 7.
8.

Nathan Ellis - Ellis has grown into Australia's best fast bowler outside of our Big 3, and has been pretty good across white-ball formats. He is probably the 4th best pacer in both LOI formats, But I still think he is much much more valuable in T20Is, to the extent that I would start him in the full-strength T20I side. Preferring Big X and Jhye more in ODIs as of now, Ellis in T20Is is the way to go.
9.

Spencer Johnson - Another bowler from the new crop of white-ball quicks, Spencer has also played both LOI formats but is another one who I feel is far superior in T20Is. He has been excellent in BBL seasons over the years and I feel is very T20-coded, so I rate him far more in this format.
10.

Jason Behrendorff - I might again have a bit bias here, but the man was golden arm in the most recent BBL season and was very good for Australia when he last played a T20I. I used to initially rate him more in ODIs in the 2019 era, but that's long gone- he is one of the best powerplay bowlers in T20s for Australia now.
11.

:bwl; Tanveer Sangha - Sangha has played a decent amount of T20Is and has done pretty well, such that I can depend on him to make up for Zampa's absence here. He is far better a bowler than Agar, and has not proven enough in ODIs to make a case there yet, so here we are.
12.

Max Bryant - I'd run out of options for backup bat and honestly would've gotten McDermott in, but Bryant had quite a sensational season in the middle-order in the BBL, and it'd be interesting to see if he gets an Aussie cap.
13.

Sean Abbott - I don't really rate Abbott so much so I'll just have him as a backup. He's prolly better in ODIs but based on the options we have there I've placed him here.
14.

Ben Dwarshuis - Dwarshuis has had a pretty good time in the last year in BBL as well as for Australia- though he did a decent job in the CT which was ODI I still think that he's a proper T20 player, he literally doesn't have List A experience domestically compared to his T20 performances in the BBL which have been quite clutch with bat and ball. Could realistically have him over JB in this side to add batdeep too but for now he stays as backup.
15.

Ashton Agar - Agar still finds his way into the side as the backup spinner. He's fallen off a bit and is inferior to Sangha as a bowler but is still the best backup spin option left over with experience as well.
So the T20I side looks quite balanced as well, it lacks the regular openers but the middle-order is practically full-strength, and the bowling, in all honesty is how I feel Australia should be going forward with their T20I attack anyways by resting the Big 3.
For Australia I feel quite satisfied with the balance in all 3 sides- The test side is almost perfect, ODIs lack an experienced middle-order but has potential looking at the 2027 WC, and T20Is retain a full-strength middle order and a quality bowling with a more mercurial top-order.