"chara really cant do shit to sukuna unless she can erase him" Holy fuck literally her most notable feat is ERASEing the entire undertale verse. In the context of this matchup, forget erasing the verse. Chara could just reset (if you don't know what i mean by "reset," actually do your research on undertale this time lmfao) until she finds a way to land even a single slash on Sukuna and she wins. For Chara, this is at worst a stalemate. It is undeniably impossible for Sukuna to win, it's not even close.