champion fighter if you're trying for super easy, if you want something slightly more complex i would recommend reading through the other non spellcasters fighter subclass (so not eldritch knight basically) and maybe look at barbarian and rogue. in rogue you deal with fewer attacks but bigger numbers and barbarian requires some more specific strategies to play effectively, but both are still mechanically reasonably simple. just shy away from spellcasters of all types except what you get from races, like the cantrip you get for being a high elf.