Hi,
I get all that and have autonomic polyneruopathy, IBS, CKD, FND and T2 diabetic. I'm Autonomic end stage with weeks to live. Considered rare, untreatable and incurable, but still fighting it anyway I can. I would be asking or looking at Dysautonomia which is everything to do with the autonomic nerve and FND. Autonomic neuropathy can be caused through long covid, champylocater and many serious stomach problems. It can also be caused through natural attrition if you are unlucky enough. Many diseases are associated with autonomic nerve damage, like MS, Parkinson and more. Few medical people even consider it through ignorance and poor diagnosing skills. I'm having to educate the medical people around me every day. When the penny drops I can see the light go on in the eyes. I don't know if they bother to go and research the subject but hope they learn from my interaction with them.
Good luck.
Cheers