Panzerfaust is too 'German' to be used. It would have been an option maybe if TOV hadn't brought us the wonderful/characterful AT rifle which we use.
Lend lease Bazooka was the other option...
All sides used captured equipment regularly. This was more so when those sides where winning because they would capture territory and all enemy equipment that were damaged or left behind.
It is notable that the germans used alot T34s and other equipment until 1943 while the Soviets used alot german equipment from 1943 onwards like Panthers/Stugs/Pz3s.
In particular they had even formed a specialist unit with 3-5 panther tanks which were regularly maintained and replaced. Panthers were highly prized by all tank crews and these were given as a 'reward' to very good tank crews. Tigers were far fewer and less likely to be captured in repairable condition. Also far less likely to find/scavenge spare parts for them to keep them running
Awww yes, we know our stuff