Such a TL would basically have a "what if Brazilian politics in the 1920s were stable" theme to it, as a mild spoiler
Feels like the 1920s will be bad for just about everyone to some degree or another.
Places the 1920s will be bad for, in no particular order:
The CSA - Obviously
Chile - gonna take a long time to pay back all those reparations
Brazil - This timeline's version of Italy's "mutilated victory"
Uruguay - A Brazilian vassal where the minority rules the country and the majority is second-class
UK - This Jix fella sounds like a real treat and they still have to deal with Ireland and India, plus a beefed-up Germany on the continent
Canada - It has been mentioned that a huge part of their economy is selling agriculture to countries that can't get American/Argentine crops, so as soon as those markets open up and trade gets back to something approximating normal Canada's in for a shock. Plus the usual Orange Crush shenanigans won't help
France - RIP to the Second French Empire :/
A-H - I'm hopeful the Dual Monarchy sticks around in some form (its shattering was by no means inevitable OTL) but they're in for a tough time vs Germany and Italy
Denmark - Probably shouldn't have shackled yourself to a corpse in Napoleon V's France
Mexico - I think it was mentioned earlier that Max's kid is a mediocre empire but then Max's grandson is a good one? If so, Mexico might be in some rough days in the late teens/early 20s, but not nearly as bad as the CSA/Chile/Brazil
Italy - Gonna have to fight A-H
and France. I can see this going poorly for them even if their side wins.
Portugal - Their economy is a complete fiasco and I can see the UK/Germany picking off parts of the Pink Map.
Colombia? - Being France's South American de facto colony might end up poorly for them once France implodes, but it is tough to say
Places where the 1920s won't be horrible
USA - Seems like all their Bad Times are right after winning the war, by 1920 or so it seems like the ship has been righted somewhat?
Argentina - Even in victory they lost a ton of men, spent a fortune, and "lost" Uruguay. Getting all of Patagonia and TdF back helps tho
China - If the multi-sided civil war ends anytime soon, but still miles better than OTL
Japan - Haven't done a Japan deep dive, but I don't think we're getting the rabid militarization we got OTL in the 20s and 30s
Russia - Way ahead of OTL, especially if they make bank selling stuff to Germany and A-H
Ottomans - Depends on what happens with Greece and Italy, but they should be in halfway decent shape, especially if they keep all their land
Spain - Should be ok? Have the ticking time bomb of Cuba/PR/DR though
Peru/Bolivia - Especially Bolivia. Getting an outlet to the Pacific is a huge deal, even if the nitrates aren't worth a damn anymore.
Venezuela? - The opposite of Colombia: Being Germany's South American de facto colony might end up great for them, but it is tough to say
South Africa - Seems like a decent place all things considered
Australia/New Zealand - No WWI means way more immigration from the UK, especially if the mother country is a shambles
Obviously not a complete list and if I'm missing something please feel free to chime in.