HOI4 seems much improved.
Have been playing as Germany from a 1936 start, trying to more or less follow a historical timetable.
Barbarossa seems to get bogged down fairly quickly. June to December and I'm as far as Kiev, still, stuck in the Pripet Marshes and have 'liberated' half of Latvia. 120 infantry divisions, 12 panzer divisions, 4 PzGren divisions, 10 Slovak divisions, about 1,000 CAS and Tac. Need to replace losses of tanks, etc.
First, I do play the historical mode. Still, I don't follow it entirely and like to attack the USSR late 1938, so my play may not be entirely suited for you. But the very basics should be the same & I do know my WW2 history.
Since you too know WW2 history, you should also know, that infantry is not the way to conquer the USSR! Tanks are pure gold here. So much open space! If you start at 1941. Since I do start in 1938, I don't know the optimal number, but I'll take a guess & say at least tank 40 div. They cut through their lines nicely. However, it is
vital, that you replace the gaps your tanks leaves and have at least 20 div. in defensive mode behind the the earstern front lines.
Still, the Soviet infrastructure is unbelievable bad! They suffer quite a bit from attrition, while you, with your well build infrastructure in Poland don't. I like to simply hold my front lines. They'll take massive casualties due to this.
Surplus of resources is not a bad idea. You can get a LOT of Russian MICs, capturing Kiev & Minsk. Not having a surplus, makes them a waste. The German navy is much stronger, than the Russian. Still, they're pretty good at cutting off my oil supplies from Venezuela, which some times even breaks my trade ties! The US wont sell you any, no matter how much PP you've spend increasing your relationship. Once you have control in the Baltic Sea, you can convoy to Leningrad. Attack from the south west with tanks & you've opened up a whole new front.
Genuine CAS & small fighters are quite bad here. Small fighters are prim. for home defence. Heavy fighters & tac. bombers are your best mates here, small fighters & WW2 CAS are for France & Britain. Oh, and don't do night raids, even with air superiority.