I love these Axis overpowered threads. Actually, between veteran players, the Axis needs a few extra units. But, the Allies do take some time to figure out and are often underestimated.
For R1, I would attack West Russia and stack Caucuses, or West Russia and Ukraine. My purchase would be 3 inf, 3 tanks to prevent Germany from advancing and holding Karelia or Ukraine. Russia can often hold Germany back until the Allied shuck is in place(more on that later). Stacking Karelia isn’t a good idea on R1. As you noted, Germany can and should pound the stack. Don’t let them pound your stacks. Keep your hands off of my stack! I prefer to pull back all of my Eastern infantry but people differ on that. In any case, Germany should never be at Moscow’s gate at G3. And when Germany has strong attacking odds on Caucuses after the other Allies do all they can to support it, your best bet is to pull back.
G1: It’s understandable that you wouldn’t divert planes when the Soviets stacked in Karelia, but in normal circumstances the UK med battleship has to go. Also, I would buy much more infantry unless I was making a big attack on the Soviets as you’ve been able to. Given those conditions, Germany’s moves were good.
A more typical UK/US strategy would be the shuck. This is building up transports and landing troops over Africa and Europe. If it’s safe, the UK builds inf and fighters and can go to Algeria first turn with the USA. Otherwise, the UK can build transports firs turn. The UK is in Norway no later than UK3 barring bizarre circumstances. From here, they build up in Norway until they can safely stack Karelia. All the while they threaten WE, Ger, EE, and Karelia. Another important piece is to position your planes to kill both German navies early on. For example, I sometimes move my British fighters to WE first turn.
As you’ve learned, the Indian factory is usually overwhelmed quite easily. I don’t recommend it unless the Allies are all working together to stifle Japanese growth. I’ll leave that topic to someone who knows more about it than I do. Since those units aren’t tied down defending India, there are a lot of options for them. Mix and match. It’s possible to counter Egypt with as much as 3 inf, fighter, bomber. The Kwangtung transport and Solomons sub can be attacked. The Indian fighter can go to Buryatia(if stacked), to Egypt, or to the Hawaii seazone. Often, I’ll combine the India and Aussie ships to threaten Africa and the Middle East.
With Japan, I prefer to build up transports on J1 and J2 so my first factory goes down on J3. Using transports is faster than the 2 IC build at getting units to the front(but not for tanks), provides potential fodder for a US Pacific strategy, and can land Africa, the South Pacific, and North America.
The American strategy looks pretty good. With that start, you’ll probably want to move to the North Atlantic to continue the shuck with the UK. You don’t mention what you do after landing Africa. When I started playing, I was logistically stupid and instead played a Pacific strategy because I couldn’t keep my transports straight. Maybe you’re better than I was starting out and already know this. Anyhow, if you haven’t used it yet, the US will need two sets of transports. One shucks troops from Canada to the UK. The other set follows the British fleet and lands troops from the UK into Europe.
Overall, I think with good Russian play and the Allies playing a KGF (Kill Germany First) strategy, you should see a string of Allied victories.