Probably a long shot, but have you ever gotten a Lyme test? Tinnitus is a common symptom if it gets into your nervous system, and the other symptoms you describe fit too.

Anecdotally I was having a bunch of bizarre symptoms this summer and thought I had long Covid too, and ended up in the hospital due to heart complications which turned out to be from Lyme. They treated me with the standard antibiotics and I’ve been pretty much fine since then.