Maybe you've heard this already, but biggest tip is exercise that doesn't require you to be upright. Recumbent bike, swimming, yoga/bodyweight exercise as long as they're done on the floor (so no yoga flows that involve a lot of getting up and down over and over again)... Those are all good for me

I like swimming especially because it keeps me from getting too hot

Lifting weights in bed helped me a lot! I can do it while working on some tbh info else and it doesn’t require standing

I agree with the non-upright exercise. I do floor exercises and mild walking when I can

Muldowney protocol and seated exercises like weighted curls, shoulder press, leg extension, etc

I do a slow walk on the treadmill!

Try looking up the CHOP protocol! It's designed for POTS patients and has a 80% success rate of either remission or something close to it.

Hi! I am the same way where I will go on a short walk and end up totally disregulated- I used to be extremely athletic as well! I used to work out for an 1 1/2 and high intensity, so I extremely relate to your issue!! The only thing I have found that is even close to working out regularly is swimming! It keeps my heart rate lower while working out my whole body. Lifting weights while sitting can still arise some issues, but it can aid in instances where you want to target a specific area. I would recommend any workouts that are within a laying position! But swimming is the one that I felt the most active, especially as someone who wants to maintain weight homeostasis, and is fulfilling emotionally.