Normal character progression

Hello :) most likely extremely noob question, however many years ago I played some of my characters and I never really got any gear on them during the season (compare now when I have Tuvala on my new char etc) /they are level 54-59 and I was wondering if there is a way to progress them at all on normal servers? I have some bound skins on them so i dont want to delete/remake them into seasonal..my current character is around 230ap compare to those older champs with like 140ap at the same level...

Thanks :)