Interesting. People with TMJ seem to suffer from tinnitus more than twice as often as other people:
https://pubmed.ncbi.nlm.nih.gov/30125964/
Let's see if there are studies about treating tinnitus via treating TMJ:
https://pubmed.ncbi.nlm.nih.gov/?term=tinnitus+tmj&filter=pu...
My reading of it: Two of the 7 found studies seem to be relevant to this question. Both seem to indicate that treating TMJ also treats tinnitus.