Then you should really only consider mass surveillance via cameras as a "big" concern. I'm not much of a travel guy, cause being handicapped has it's downside, but afaik there aren't many cameras spread across Europe, mostly near/on main train stations, public transport and similar public places. Use a cap/hat and maybe sunglasses. I haven't heard of any AI/biometrical real time/logging/analyzing being used in production yet (but it's being discussed). Don't use public wifi, get an anonymous simcard (roaming data esims for some crypto-dollars) and a GrapheneOS Pixel smartphone (use it only when needed). Pay by cash and be nice to other humans. And don't think too much about stuff you can't control! Don't let you get mad and restrict your life too hard because of stupid politicians and governments xD

Have fun exploring Europe! Take a look at Italy, Austria, Germany, Switzerland, France, Belgium, Netherlands. Poland and the Czech Republic are nice too, but it's harder there to communicate in English IME.

oh: and as a drug user, usually prescribed opioids (no abuse, I need them and have a prescription), but (a)busing weed (got a script too, but usually buy from the dealer/vape HHC currently) and hallucinogens/"fun"-drugs (LSD, Shrooms and Special K), I only had problems in Germany because of THC (haven't had a script at this time). But usually it's OK to party, but don't be too open about your use. Funniest moment was in Amsterdam. Some friends and me were sitting on a bench near a little garden, drinking beers and smoking some Js. When the police drove by, we first wanted to hide the Joint, but remembered ah, no public booze in Amsterdam, and had to hide our beers instead. It's usually the other way round :P