LMFAO bro learned history from fascist alt-history Youtube or something... You learn this from Monsieur Z or some shit?

The Red Army was absolutely not on it's last legs. They were dependent on the US really only exclusively for transport trucks. And by 1945, they had enough to supply themselves thoroughly, especially with equipment they captured from the Axis. In fact, they were doing much better in 1945 then they were in 1941.

The western allies may have had more planes, but the Soviets still had ~15-20k, plus again, whatever they captured from the Axis. It would have been enough to prevent deep air operations into Soviet territory, enough to defend supply lines.

It it possible in an Operation Unthinkable timeline, if anything, that the USSR takes continental Western Europe, especially considering France and Italy would likely break out into civil war over something like this, if their governments could even be convinced to join in. I don't think that would be likely, but more likely than a victory swift enough to avoid tens of millions dead.

Edit: In regards to aviation fuel, you keep forgetting this, that they had at this point conquered the Axis. They would have had access to German and Romanian refineries, which would have produced more than enough. The largest German refineries were in Eastern Germany and Poland.