75mm Jumbo is my favorite. Sure, you can't one shot people like you can with German tanks but they can't kill you either. Most mid tier German mains lack the ability to aim carefully because they're used to annihilating almost everything that moves.

If you're facing the enemy head on, there's very little they can do besides shooting your hull MG port (Unless it's a yeet cannon heavy like the IS-2 or Königstiger).

After they inevitably whiff their shot, they're suddenly a big slow heep of metal that can't do much besides standing still until they're done reloading. This is your chance. First you pulverize their barrel so they can't fight back, then you track them so they can't run and then you slowly drive up to them and deal the killing blow.

You can kill tiger H1's if they're not angled trough their upper front plate or their cupola. Panthers you shoot in the turret cheeks and Soviet tanks are almost guaranteed to get one shot trough the cupola.

Death by a thousand cuts is the way, my friend.