My first experience with this was last year, when I joined a drop-in 5E game playing the Rime of the Frostmaiden campaign. I rolled up a Northerner human fighter, sort of styled after Herger the Joyous from the 13th Warrior. He'd fit right in, right? (This was the fighter who was sort of also a rogue that I mentioned in a different thread, based on his build)
Well, the other two 'main' players (as in they showed up every session) played a damphir(?), half-vampire something warlock, and his girlfriend was playing some sort of turtle character- I can't even remember the name of the race. Another guy who played a couple sessions brought his dog with him (literally) each time, and changed his character every game to something different.
I lasted about 4-5 sessions, and finally just subtly bowed out. I tried, I really did, but the fun factor was ZERO.
In terms of trying to put new campaigns together in the future, I'm feeling like the only real choice is to abandon 5E completely and go OSR, probably back to 2E, which I really enjoy, and then house-ruling out the glitches in that system.