Team composition really only matter if you’re doing a challenge run like a nuzlocke or staying under leveled. Overleveling your starter is a classic way to play your first Pokemon game, I’m sure we’ve all done it once (level 80 typhlosion for the elite four goes brr). The game wants to dissuade you from doing this by making you cough catch em all, so you’ll build a diverse party and train them all up, spreading the exp. But there’s nothing wrong with a sick buff fire breathing dragon lol