I went through an 18-month benzo withdrawal about 20 years ago, so I know what you're referring to. Afterwards I discovered a micro-current device called Alpha-Stim that helped calm my brain and neurological systems down considerably, and felt I would have had a much easier time with my benzo withdrawal had I had it during that time.
I didn't have my first experience with HBOT until about two months after getting drug-induced tinnitus on Feb. 4, 2018. The drug (Promethazine) completely whacked out my brain and neurological system--along with giving me screaming tinnitus. I truly wondered whether I would ever be able to relax again.
About half way through my first HBOT session, I was actually able to relax again. I then bought my own unit, and did 3-4 sessions per week for a little over a year, until it got burned in a S. Oregon urban wildfire. I believe those sessions went a long way toward stabilizing my brain and nervous system, and also believe it would have been very helpful during my benzo withdrawal.
I recently had another experience that helped calm my brain and neurological system down that's much cheaper than either Alpha-Stim or HBOT. It's a different kind of micro-current device my chiropractor used on me, and I found it profoundly relaxing. He sent me links to order it on Amazon, but I can't seem to find his emails. When I get it, I'll post the information. The device and app together comes to about $150.