It's hard to say what I'd recommend for a 1 player run because I didn't really do those. I think I'd go for a solid "base" class like a warrior, barbarian, wizard, or something. Ultimately it'll always be difficult though. Maybe something ranged like wizard, arcanist, or tinkerer is actually easier when playing solo because you can stay out the range of most enemies. But when they get close, you'll probably get killed because there's no-one to protect you.

Ultimately, if I were you, I'd just play whatever I want. Dying is extremely common in this game, so just accept that, have fun, and get better.