Strongest Aient Transmigrater

Goes to the past gets a System Typical meets dinosaurs and shit like that gets op quickly cause I don't like weak MC kinda smart and dumb at times probably cause he has brain damage like me my first novel if it gets popular I'll continue if not the NOTHING I'd like some ideas aswell Btw the pic ain't mine but this is mc design for me but if it doesn't look good please give ideas*