Ive tried all the 1941 ToW on General, and the KV- 1 and t34 are impossible to counter (also, certain times the t70 and m3 have a ton more health for specific missions).
Pak40 is the only weapon that can harm them, but ive managed to beat the VP battles with mobile defense, since the puma is a life saver and ostruppen spam works against AI.
Given how bad the panzerbüsche is, i dont know why the PTRS has to be doctrinal...
PAKs and Tellermines will be your friends; you can try snaring with AT Rifle Grenades but the Tellers really make sure
Later I realised tanks were a waste and used Osttruppen fuel to Munitions to get loads of Tellers (then spam Railway Artillery)