I've been having some luck with curcumin for somatic tinnitus. It hasn't fixed it, but it's become quieter after 5+ years of continuous ringing.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5063744/ (fibroblast damage treatment)

https://onlinelibrary.wiley.com/doi/abs/10.1002/lary.25031 (protection against paclitaxel-induced inner ear damage in rats)

https://link.springer.com/article/10.1007/s11356-022-21932-1 (another examination of protection against ototoxicity)

There are other studies where an extract is injected and arrests hair cell damage then regenerates things. It's not well understood whether taking it orally would have the same effect but there's anecdotal evidence of it settling down inflammation and changing the quality of tinnitus. I've experienced it myself and my wife is in the early days of trying it out.