I sprained my ankle last year but after that i did mostly yoga or I would lift weights. Then if the ankle healed more I would walk for hours, and then I would start going to the gym again and running but because the gyms are closed, I would run.
I do this thing called bicycles which is where you lay on your back and pretend you riding a bicycle in the air. It works out your abdomen and won't put a lot of pressure on your ankle
Ive been working hard on my and right now and that can include simple things like toe touches or big things like flutter kicks that don't require much to any stress on your ankle!
Stretching and easy yoga after a hot shower is probably good, but know your limits! Working up from light walking (with good cushion) to walking in terrain is good for your ancles and knees, but don't aim too far! Remember that downhill is challenging on the knees and ancles.
I have sprained my ankle before, so I get you :)) to be honest there are lots of exercises tgat don't include moving ankles or legs in general. As surprising (at least to me) as it sounds, stretches you did at school are pretty effective! They stretch the whole body separately by body parts so you can just skip the leg exercises and you still stretch well.
Good exercises to do after recovering from an ankle sprain are stretching the ankle, putting a good amount of pressure on it and keeping a daily time to workout the ankle.