I hear you, I had a bike taken piece by piece aver a couple days. My university had a no bike in room policy so I had no option but to lock it outside. They finally let me take it in when it was nothing but a frame and rear wheel.
I agree a dropper post would be easiest to steal, someone would just need a multitool and housing cutters, I bet 30 seconds or less and it could be gone. It’s small and expensive.
An off size/different driver would be best but other than custom made I’m not sure where to find them. Hopefully someone has a good suggestion.