There's a few things that seem to actually reduce the volume for some people, but they are not guaranteed to work for
you. Many studies track the actual volume through the treatment. Other studies focus more on the psychological aspect of it with the traditional T questionnaires.
Vagus nerve stimulation, rTMS, tDCS, DBS, etc... are all experimental but some of them do show statistically significant results on a subset of patients. Maybe you are lucky and it works for you, but you could also be unlucky and make things worse (there is no risk-free option in healthcare).
One approach would be to try them all, but of course it's not that practical because there's the issue of time (treatments are long, and you don't want to mix them), cost (some can be very expensive), availability, etc...
One thing that is fairly easy to start with is sound therapy. There's a few types of therapies (notch, windowed white noise, ACRN) that you could try at variable cost tiers. There are the traditional providers of such therapies if you go to T clinics, which offer you support/counseling/etc for a premium. If you are disciplined and a tiny bit tech savvy, you can find other providers that may be more convenient (i.e. over the internet) and for very reasonable costs. For example you can find "a la carte" purchases of sound therapies (windowed white noise, ACRN, notch, nature notch for sleep), or a monthly subscription for notched treatment, or even listen to the free ACRN generator from GeneralFuzz
here.
Good luck!