But does the limbic system have to do with the volume of the tinnitus or not?
Supposedly, yes
https://www.cell.com/neuron/pdf/S0896-6273(10)00325-9.pdf
This might explain the tinnitus saying, "the more you fear it, the more you hear it"
The idea is something like -your brain labels it as something to be feared and this can amplify the sound perception.But it is a complex disorder and it's not the same for everyone. I genuinely do find that if I am busy and distracted mine is more likely to go through a quiet phase, not habituation, actually quieter. Other people don't seem to find this
With many chronic disorders in medicine, there is a LOT of mixing up of people's reactive distress to a condition, versus the actual severity of the condition. Like yes people do very a lot in how they react to particular things, but this isn't the same as the actual severity
You could say that any untreatable chronic disorder is 90% mental, in that the only thing we can change the reaction. But it doesn't necessarily follow that the condition is fully controllable by controlling one's reaction. It still might be really severe no matter how you choose to react. There may be some modification of actual severity according to stress, activity in the limbic system et cetera but may only have a small or no affect for many people.