I have vertigo issues and have wondered whether scuba might have contributed to the inner ear damage that causes it. It was either that or, also like you, sinus issues.
During the diagnosis phase of my vertigo I learned a few things about how primitive medicine still is when it comes to inner ear issues. If the problem isn't BPPV, some large growth they can cut out (e.g. a fistula) or something that can be "solved" by just destroying your inner ear (gentamicin therapy) there is almost nothing they can do -- and in fact they can't even really diagnose the issue, just test out different therapies to try to find anything resulting in some mild improvement. Most doctors have no idea what the possible diagnoses even are; the specialist who eventually helped me was a neuro-otologist, which already seems unreasonably specialized, and he said he only really had an idea because his son had the same issue as me.
During the diagnosis phase of my vertigo I learned a few things about how primitive medicine still is when it comes to inner ear issues. If the problem isn't BPPV, some large growth they can cut out (e.g. a fistula) or something that can be "solved" by just destroying your inner ear (gentamicin therapy) there is almost nothing they can do -- and in fact they can't even really diagnose the issue, just test out different therapies to try to find anything resulting in some mild improvement. Most doctors have no idea what the possible diagnoses even are; the specialist who eventually helped me was a neuro-otologist, which already seems unreasonably specialized, and he said he only really had an idea because his son had the same issue as me.