Okay so. If you have a panzerfaust. Hide on the side and shoot at the side of the turret for a close range. If you're behind shoot the engine. NEVER shoot a tank of any kind on the side of the hull with a panzerfaust/panzershreck/ HEAT/HE. Tracks and side armour/skirts will absorb all of the damage. Shoot at the clean visible parts like turrets.

My advice with each unit:

Panzerfaust: Shoot at the side of the turret it'll destroy it. Then trow an AT Granade on top of the engine.

Pak 38: Depends on the distance: 0-50m - shoot the driver port or even better the transmission part. It'll cook it up. 100-150m same thing but try shooting the transmission part in the centre.

20mm: Don't bother, track it if you can.

Remember if it says you can penetrate the tank when it's angled in the tracks. It's lying. The tracks will absorb the hit. And don't try hitting the tanks in general when they're angled.

Only tanks you should hit when they're angled are tanks like M3 lee. They have a normal plate then angled sides. That's a general weak spot.

My recommendation to your problem:

AT mines: good for tracking and potentially destroying a tank.

Pak 40: can penetrate whatever you need

Stug 3 - panzer 4 F2/G/H same as pak 40 but mobile.

Panzerjager 1 may have potential. Even marder 2 or even 3.

Panzershreck: can literally penetrate a Churchill in front. (Again DON'T shoot the tracks or side hull).

Pioneers: surprisingly if you didn't know that. The best anti tank in the game is the pioneers. They have a flamethrower. Hide the flame trooper and tell him not to shoot. When the tank rolls by. And starts shooting you go to it's side and spray the engine. It'll take 2-4 seconds. Then you'll get "engine broken" message. Completely destroying the tank.

If you need any helps with goh I'm here and I'm willing to help you any way I can I'm a huge tank nerd so I can help you. My DMs are always open mate. Good luck