And as amazing as that was, it's still nowhere close to the full power of One For All.
I think this episode cements that Mirio isn't getting his quirk back for quite a while, if he ever does. Eri would have killed Izuku if One For All didn't allow him to constantly destroy his body to counter her quirk. It could be years before Eri has the fine control necessary to give Mirio his quirk back. The look on Nighteye's face when Izuku told the future to go pound sand was great.