Red Flood is a mod for HOI4 and still in development, but I just wanted to recommend it as an example of non-plausible alt-history being fun as hell.
Does it make sense that a schizophrenic (iirc) artist takes over France in the name of Futurism, and can then go on to declare war on reality or go full primitivist and make France into Gaul again? No.
Does it make sense that some random esoteric socialists (who honestly took too much mescalin) in Altai can reunite Russia and make it into a decent, if weird, place to live? Not at all.
How about a former Bolshevik taking Technocracy literally and to it's logical extreme, replacing everyone's names with sequential letters and numbers while completly capital-R-Rationalizing society and founding a country named the One State? Absolutely not.
Also as of the most recent update at time of writing, Futurist Stalin.
Is it fun as hell to make and see that happen?
Yes. It's partially because there is some genuinely good writing - not TNO level, but they give a sense of how things really are better than just descriptions on national focuses - but also because it's willing to be absurd and own that fact.
It doesn't shy away from the fact that, yes, some ideologies and governments are going to kill civilians and destroy infrastructure for various reasons and that's something you, as a player, have to reckon with if you want to play those paths/countries, both in narrative events and through gameplay effects such as losing manpower/population or factories.
So, yeah Red Flood makes no sense, and I wouldn't have it any other way.
(Also Germany is a Spartacist Council Republic at game start, so there's that for all the non-authoritarian socialists out there, though Goebbels can come to power and do some weird Socialist Nationalism thing, though I don't think he hates the Jews, so there's that.)