Had an interesting MHA dream last night, of basically how this might end, which felt pretty authentic.
In it what basically happened was that between Deku and Nana, they're successful in bringing back Tenko Shimura, separating him from the person that he became, but in response his Shigaraki body and persona basically lost control and went berserk, with all the quirks he possessed destroying his body. Naturally Deku gets pretty emotional, and is unable to do anything to help him, but Nana assures him that this was the best possible outcome all things considered, her remaining by Tenko's side as he dies, with Deku finding himself back outside on the battlefield, being the only person left after all that. I think he still possessed OfA, but there were no other vestiges except the one of All Might, and I guess maybe the first user, but I think he ultimately bid farewell to Deku and passed on, leaving the quirk in his hands, claiming that he doesn't need anyone to guide him anymore.