Same. But I've never heard of anyone having hissing after an ear infection for 6 years. Have you checked out your ear with one of the earscope cameras you can buy off Amazon? You'll be able to see if it's retracted or not (slightly sucked in).
Have you not been given nasal sprays to help ease this?
I'm chuckling as I read this because yes, I've had everything that you mentioned and more including multiple surgeries. This is not my first rodeo
I was interested in your experiment with rubbing your jaw and Capsaicin because I'm always looking for ways to ease a flare up when the tinnitus spikes. Rubbing the mastoid area sometimes helps, but I hadn't really focused on the jaw. Turns out it doesn't help, but it was worth a try.
The reason I have tinnitus also has to do with hearing loss, though I had hearing loss for many years before the tinnitus (go figure). An ear infection somehow triggered it. Once triggered, it didn't stop. It's most likely a brain thing. And a big question is why tinnitus goes away for some, but stays with others. Millions of dollars are being spent researching this. I would love to be able to just fix it with nasal spray.
About the hiss, one of the many, many, many audiologists I've seen told me that the reason some people have a hiss rather than a tone is that the hiss sound is the same frequency as the hearing loss. So even though it is a hiss that sounds like air or wind rushing through a pipe, it is not the actual sound of air going through the Eustachian tube, it is just the brain playing tinnitus at a frequency the auditory nerve misses. It's filling in the blanks, so to speak.
You mentioned Eustachian tube dysfunction being a marathon, not a sprint, and that is SO correct. I've experienced that along the journey and, once it gets clogged, it takes a while to clear up. If your tinnitus is caused by ETD, keep being patient and using all of your sinus clearing tricks. You may find the tinnitus sticks around for a while after the ETD is fixed, but if you don't have a permanent mechanical hearing issue, it will probably fade away.