Izuku learned how to weaponize his muttering during the Overhaul arc
Izuku after analysing Confession decided to tell everything about himself and other things and continue fighting the fused Overhaul who was firing confession at him. Eraserhead was making sure Overhaul was not able to use his Quirk and Mirio was moving Nighteye (who lost his Quirk to the Quirk destroying bullet). In that moment Izuku got inspiration from Overhaul.
Izuku "Separate the power"
He began separating OFA into two pieces the 2nd piece being much smaller than the original finally getting something worthy of calling
" Ultimate Move: OFA full cowling Double Core".
now he can handle 25%.
Meanwhile Eri was taken to a safe place immediately after being found.
(Everyone I thought this idea was good and it actually make sense to me so let me know what are your thoughts on this idea 🧐)