Hi,
I think I might be able to help but as you have already been down the vestibular route I realise I may come up against some scepticism.
Many years ago I suddenly developed ear fullness, dizziness, fatigue, terrible brain fog and after a while full blown vertigo attacks or just a sensation of movement when there was none. It was constant and my life was miserable. I saw 2 ENT doctors who tried to fob me off as suffering from anxiety. One briefly considered menieres disease but as I had no hearing loss discounted it. This went on a for a year with no one able to tell me what was going in. Some luck meant I came in to contact with someone who had the same condition but knew what was wrong. I learned that ENTs do no further training in dizziness and know very little about it beyond the basics on labyrinthitis. GP's are also often extremely ignorant on the issue. Anyway, long story short, I ended up seeing first a neuro otologist (specialist in balance disorders) who initially diagnosed vestibular neuritis (labyriinthitis by another name.) When vestibular rehab made me worse I was sent on to neurology who diagnosed me with what I had, migraine associated vertigo - aka vestibular migraine.
Not all neurologists are equal when it comes to migraine, it needs to be a specialism or they can be woefully ignorant about it, which is why the the fact you have seen a neurologist doesn't deter me from thinking you probably have this. My neurologist is a big name in the migraine field called Professor Goadsby - I am lucky in that he happens to be in the NHS hospital in my catchment. He would tell you that migraine is not a pain condition but a neurological condition that can impact different parts of the brain. It can also suddenly morph and change over time. You can be someone who gets the headaches who suddenly becomes someone who gets vestibular symptoms. People can have both pain and vestibular symptoms. The symptoms can be constant or intermittent. It is a diagnosis of exclusion, there is no test that will tell you you have this. Once other things have been ruled out, then it is highly likely the cause is migraine, particularly (although not a necessity) if you have a history of other types of migraine.
Have a look at a support group on facebook called, rather strangely as it's for anyone, not medical professional, 'vestibular migraine professional.' You will find a whole load of people with the same symptoms as you. The condition can be managed with daily migraine preventatives. I spent many years on propranolol mostly symptoms free if I managed my lifestyle, having been dizzy previously for 2 years straight.
With menopause the propranolol stopped working and my migraine came back, although more pain based than dizziness, managed now with occipital nerve blocks which work better for pain.
I would urge you to do a google search on migraine associated vertigo. I saw your post and wanted to help as I remember the despair of not knowing what was wrong and feeling that way. Hormones may play a part in this but the likelihood is if they do it will be because they have stirred up an already existing migraine condition. I take HRT which also helped when I got crippling pain based migraines when my meno kicked in. Although progesterone can be very rough on migraines which is why you might have had some struggle with introducing hormones. I noticed you mentioned migraines in another post which is what made me pretty certain this is probably what you have. You sound just like I did and indeed all the people I have got to know on the migraine associated vertigo support forum over the ensuing years.