I can see your point, in my hypothesis, the psychedelic therapy would speed up the re-conditioning and recovery of depression and anxiety, which are highly correlated to tinnitus. As commonly known, some people without hearing loss (even when tested in the high frequencies) still have tinnitus, so that may be affected by somewhere in the brain (DMN, brainstem, auditory cortex, whatever affects hearing, attention, and mood). I can attest that I suffer from anxiety and depression since late childhood, and I did not have noticable tinnitus back then. It wasn't until my early twenties when I graduated college and got into the world of work and careers (which I hate) that amplified anxiety and depression, and that was when I started learning and reading about tinnitus because it started to become intrusive. I was able to hear up to 18kHz up until mid twenties, and at age 30 now I can still hear up to 16-17kHz (and still have bothersome tinnitus).
Paul Stamets has something to say about lion's mane mushrooms and psilocybin mushrooms affecting "neurogenesis" and repairing auditory neurons. Although no additional larger scale research studies have been conducted, I think it's worth looking into:
https://medium.com/psychedelic-fict...-mane-protocol-good-news-it-works-3cfd6d9f08b
He's been doing a lot of great work in his field and I do not associate him with pseudoscience or snake oil at all. He's just ahead of a few scientific communities lagging in research at the moment. Here's some preliminary research (see section 4.6):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5987239/