After Long covid I was treated for POTS for 3.5 years - meds didn’t help and I steadily became worse.
LAB tests and CAT scan normal.
I finally saw a neurologist and had an MRI. Spinal tap scheduled.

The MRI showed fluid buildup in the brain. NPH Normal Pressure Hydrocephalus.
Next appt is with a neurosurgeon for a shunt.

Don’t be discouraged (like I was!) bec some conditions need an MRI for s diagnosis.
I’m in a large city with lots of hospitals and it was still difficult getting a new-patient neurology appt.

I didn’t think my poor balance, bad leg, weak extremities and urinary urgency were related.
You could have many diagnoses, not necessarily mine, but if labs and X-rays were ok. Keep seeing docs.
I’m now a fan of MRI’s and neurologists since that led to my diagnosis!

Don’t give up looking for answers and ask to be put on appt waitlists if there is a long wait.. Check back for cancellations even if on a WL.
Good luck!