Without knowing more about your conditions and symptoms I would have to agree with the rheumy or pulmo treating your sarcoidosis. If your sarcoidosis is stable and not requiring biologics at this point, then just treating the POTS is reasonable and appropriate.

It doesn't sound like you have much involvement with the SFN...other than some tingling and of course, the POTS. Therefore, I don't know if any treatment specifically for the SFN is necessary at this point.

If things start getting out of control with SFN and POTS, then of course addressing the root cause (Sarcoidosis) would be best approach. But it seems you are pretty stable right now (a good thing) and it's always best to use the least amount of intervention as possible.

Hope this helps.