Not sure why the game needs any tweaks on that account, as you are talking about some house rules combined with nerfing Germany quite badly. The setup for Germany isn’t really the problem, its the fact that SBs are OP by virtue of their versatility combined with the fact that Russia is too weak and poor to do anything about Germany much less the other 2 angry Axis is the core of it.
Unf, if you make Russia even a bit tougher, you make Germany’s job much harder and it will need the full commit of all 3 Axis to kill USSR, which makes the game less versatile because other strategies that don’t tackle Russia first and focus on it will become less viable.
Really, Russia’s starting weakness does fit with the 1940 game and history, what doesn’t really fit is that by 1943, Russia would have more tanks (and better) tanks than Germany, which is not how things play out in the game (since Russia doesn’t really increase in power since it is under so much pressure from game-start).