Hello Timelord, welcome to the forum!
Against a seasoned/strong axis player, Russia cannot survive on its own. Period.
They need massive aid from their so called ‘allies’ and they can give it in more than one way.
The most obvious way is to channel some allied FTR into Russia (anywhere is possible, but most notably Moscow). By the time Germany can attack Moscow, the allies can have >10FTR there (so, on top of the 2 Russian ones).
The other way the allies can help Russia is to (threaten to) open that 2nd front asap (US/UK5 at the latest), while also threatening to 1-2 Berlin (USA grabs Norway + Denmark, then the UK and/or France lands in Berlin). This may require some to a lot of practice but it is very dangerous for Germany so they cannot be ill-prepared here or the axis loose the game instantly.
The allies must carefully balance their resources in 3 areas:
1 Western Europe
2 The center (Russia/Moscow)
3 Against Japan in the Pacific
Many allied players have a lot of difficulties with exactly this balancegame, which is the culprit for lots of lost allied games. If they allocate a little too much resources to one of the above areas, a seasoned axis player will more often than not exploit the resulting weak spot in (one of) the two other areas and create an axis victory.
As a very simplistic rule of thumb, you can say that the more Germany focuses on Russia, the more FTR the allies need to send to Moscow, but not so much that their Western front will suffer.