I am relatively new to POTS (3.5 years so far). I have read quite a bit, but only a small fraction of what's out there.
Bottom line, there is very little known about POTS. There is no reason to expect that your POTS will last forever.
Even the diagnosis of POTS is simply the existence of numerous symptoms for at least a minimum span of time.
I get a kick when a new medical professional asks if i have been "DIAGNOSED" with POTS. After 2 years, i was finally offered a Tilt Table test. By this point, i already had a heart loop recorder implant that proves the high heart rate when standing. Just over 200bpm when i stand was my max, typical was 145 to 175bpm. But by this point my body had mainly stopped dropping the oxygen% and so it wasnt leading to near fainting anymore. Anyway, i could speed another $3000 to have this test which wont help anything but give a diagnosis title.
Sorry, sidetracked, bottom line, POTS starts with little reason and it fades or morphs too. I think that as they learn more about viruses, they will find that most things that they currently categorize as autoimmune are really still viruses. Covid infected so many people that the new sheer volume of patients will help solve this puzzle for the all of us. Watch new studies, but most importantly, help yourself by doing what you can, when you can. It will help emotionally and it will help physically like climbing out of a canyon, little by little. Accept improvement as improvement, and accept a setback as inevitable, but temporary until the next improvement.