AFAIK, Garg and YG are right.
Consider 2 loaded CV in SZ102, and 3 STRBombers in EUS. No early JDOW, so USA has 20 IPCs less first 2 turns.
Germany can defend SZ110 with approximately 1CA + loaded 1CV (4units, 5hits). Sometimes they also have their BB left, but then the UK also has more ships left.
Anyway, with this warfleet and London captured, Germany can barely keep Russia out of Eastern Europe, especially if the Kriegsmarine is destroyed (no land units being retrieved from there). If Germany invests in a bigger warfleet, I am afraid they cannot hold off Russia anymore.
Back to the USA. They can have 7 aircraft attacking (indeed surviving STR landing in Eire) and 6 loaded TRS, or, at the expense of TRS, buy even 3 more STR (for a total of 10 attacking aircraft). All considering no early JDOW -and thus less income for the USA.
I think it is impossible for Germany to ward off both the Russians AND adequately defend its kriegsmarine.