Puma has absolutely no armor to even be effective against a T/34 and the Jagdpanzer IV gets circled way too easily. The volksgrenadiers with shreks can be effective yet they their fire rate is atrocious and get killed before they can shoot 2 rockets. The AT gun can be killed easily by 2 T/34's. And yes T/34 should get a fuel increase because they are to cheap for their effectiveness against the Germans.
If handled correctly Puma can 1 on 1 T-34/76 especially when you jam the turret. Maybe it won't kill it all the time but it's definitely capable of causing heavy damage or retreat.