Is the strange lingering taste Uremic / Uremia perhaps ??
That would indicate something is up with Kidneys …which would also tie in the Cortisol.
Have you had any sleep studies done before? Insomnia is a difficult one as 99.9% of doctors immediately assume it’s psychiatric issue and go on about anxiety/depresssion/therapy crap, when sometimes insomnia has other causes such as heart issues, kidney , thyroid, hormonal etc
In the 10 years since you quit have you had any periods at all of normal sleep / or as close to it as possible ? Tried any meds?
This has been my most debilitating symptom too, so I understand what it’s like, however I’m doing somewhat better now.
The way I look at it is this : when I was in the stage of 0-2 hours sleep a night , that was shit, I knew something was wrong, I knew it was related to finasteride.
However, When I get around the 4 hours mark (which I’m assuming is what you get here when you are awake for a few hours in the night) I think well, this is still insomnia , but it’s probably at the same level now as what ‘normal’ people get when they have insomnia , so I feel I can live with it . Generally the 0-2 hours thing was horrendous and probably the hardest thing I’ve gone through in my life , so I have learned to appreciate even a night of 4 hours. However these days I’m pulling in 6-7 hours a night which is working out ok.
Not that I’m minimizing your suffering here or trying to belittle it , because I’m not and I know the struggle myself, it’s horrendous. But I do know a lot of people who have the similar sleeping pattern as you describe who haven’t taken finasteride so it could be something else that’s crept in over the years , this could be cortisol, hormonal or even serotonin related (serotonin converts to melatonin naturally , so low serotonin means low melatonin too)
Might be worth checking out kidney function and mentioning it to your doctor, but as I’m sure you are aware they will come full guns blazing at you with the ‘psychiatry ‘ card !!