Problem is that gaba is linked with glutamate (glutamate is a precursor of gaba) and if one person has the gaba-glutamate conversion mechanism compromised some gaba enhancing drugs or supplements may become dangerous and do the opposite of what they are supposed to do. L-theanine is one example. This is good article on balancing gaba and glutamate, I posted it yesterday on a different thread
https://www.holistichelp.net/blog/how-to-increase-gaba-and-balance-glutamate/
Benzos increase gaba in a quite specific way. They do not attach to gaba receptors from what I gather. They may work short term, some people are able to stay on them long term without reaching tolerance or withdrawal, but some other people do and it's hell. It's a lottery and varies across individuals.
I tried L-theanine, taurine, gaba, and all sort of gaba-enhancing supplements and gaba-modulators in the past, and NAC that should turn glutamate into glutathione, but this didn't even scratch my tinnitus. Perhaps this stuff does not have the potency and selectiveness of gabapentinoids and benzos. Clonazepam initially was able to make me ignore my tinnitus (not to quieten it) but as I remained on a constant dosage it totally lost power and I suspect the worsening I keep experiencing might be partly due to tolerance withdrawal. I tried Lamictal to reduce glutamate but it backfired. So I think the relationship gaba-glutamate is much more nuanced than we would think.
The Holy Grail would be a drug acting on gaba without tolerance or dependence. Initially we thought gabapentinoids were like that, like "good benzos", but some harm reduction specialists I talked to told me people struggle to quit pregabalin more than benzos very often, with horrid withdrawal symptoms (including tinnitus). So it is a no-go. There is a very promising drug in phase III that regulates gaba but is not addictive, vistagen ph94b (Greg Sacramento mentioned this to me). This is very encouraging and could be the solution to finally avoid benzos but we have no idea of its effect on tinnitus. There are other gaba-acting drugs like acamprosate that seem to have no effect on tinnitus according to some studies (but do according to others) and there are quite a number of glutamate antagonists but they don't seem to help. So it's a little of a mystery why some gaba enhancing or glutamate reducing drugs and supplements do nothing while benzos seem to be generally effective. Maybe it's potency. Who knows. More research is desperately needed here, as in all things tinnitus.