Context (I started the game in 2000):
me trying to play as ukraine and like have it as realistic but idk the game is like: "ok russia starts with 35 mills (usa has 70 for comparison), 45 civs", then am here with my my like 5 civs and 8 mills and am like: "ok but why russia so op"

How I tried to balance it out:
ok I reduce russia's military factory count to 10 mills so it's more realistic and reduce the amount of civilian factories and give them crippling corruption (like irl) reduce military size to the size irl before war in like 2014, etc etc (just trying to get this game to be realistic)

What like happens for 0 reason after I just want for realism:
ok then am like: ok yeah realistic 2014 war and stuff, then I have the uprising and all, russian occupied areas only extended to those that they were irl when the conflict got basically frozen, then out of the blue the russia AI decides to declare war on me in 2015 summer

When I looked into russia AI's point of view:
I tried to know why, so I did "tag sov" and looked at the focus tree and found that somehow they just were able to gain puppet justification on me really soon and then invade even though I tried to do stuff realistically and all that and say maybe some might say yeah that ok they gain access but should declare later BUT in my experience, whatever you do, they will declare in 2015, no matter if you easily overrun donetsk and luhansk or leave them alive, it won't change anything, they will get the puppet focus and they will immediately declare war

Commands I did and then what russia AI shortly after did very unexpectedly:
ok then what I did was that I used commands to force russia to send a white peace to me so I could maybe continue my realistic game, then in the beginning of 2016 russia AI came up with the brilliant idea of declaring puppet war on Luxembourg and then promptly having war with all of NATO and just dying really quickly and decisively

A bit of ramble I guess?:
I have, NO IDEA why russia AI does what it does or why the devs decided to buff russia so much like, they might not have that much civs on their own but they get like 32 from trade at game start and idk how the developers arrived to the conclusion that russia should have half the amount of mills that the united states of america has like the russian military industrial complex is a joke compared to the USA's irl, especially in the starting year

If hypothetically an open minded developer of Millenium Dawn is reading:
Like maybe instead of having everyone give russia a ton of civilian factories (from trade) just have like petrol state and have just good earnings from modifier that removes oil and gives money in return and maybe don't have other nations so willingly buying resources from russia instantly at game start as it literally buffs them a lot and maybe don't have focus available for russia to full-scale invade a whole 7 years early (especially if you on your end have been doing everything historically) and maybe reduce the size of the russian military industrial complex to like REALISTIC levels, just saying. And maybe don't have them spam army and like reach double the amount of soldiers they invaded ukraine with in 2022 in the year 2014 in-game.