Tank Destroyer -> Counters tank
Everything other than tanks and MGs -> Counters Tank Destroyer
Simple enough for you?
Couldn't have offered more of an obnoxious tone even if you tried there, could you?
To OP: if you would like to keep trying with StuGs - which is a valid tactic and even one to be respected, as it's challenging - you can try using commander abilities to bolster them. Commanders with Riegel mines (including ones that get those via the 251 Observation Post ability), spotting scopes, infantry camouflage (for extending vision range for StuGs without that getting noticed), etc. You'd still need to disrupt vision for opposing TDs by forcing their infantry to retreat (and by using the StuG vet1 ability), but at least something to try.