What languages do you speak?
Traveling solo is ok in main cities in most countries if you don’t speak the native language, but can get harder the further into them you get where zero English is spoken.
I travel for work a lot, and have been to every major region of the world and spent a lot of time exploring solo.
Don’t get hammered in unfamiliar places, pace the drinking and keep your wits about you. (It sucks being lost hammered and can’t find your way back to hotel or explain where you need to go to taxi etc, if there even are taxi where you are!!)
You meet a lot of cool interesting people when solo, as your attention isn’t on your core group you are with.