As a person who stutters and has tried many drugs, I haven’t noticed any drug giving me consistent results. I have tried Phenibut, F-Phenibut, & Gabapentin, all of which are in the same class of drugs as Baclofen (Gabapentinoids) and the only thing they gave me was a mild addiction (which I thankfully moved beyond). What worked for me was years of public speaking. I’m a 31m and work as a tech lead for a software team. Back when I was around 16 I started public speaking at church. This continued and increased in frequency throughout college. It sucked, and was very embarrassing, but with every speech the embarrassment became weaker and weaker. And somehow my brain managed to figure out how to slide through stutter. I still get partially stuck, and still feel that tiny impulse of anxiety as a problematic word approaches, but I consistently slide through the word with only a minor block (my main problem is full blocks like you).