Similar to Tomura Shigaraki your body has undergone intense bodily modifications increasing your physical attributes on a level comparable to All Might in his prime. These Modifications don’t just increase your physical attributes as now any quirk you have are amplified as well as your body is enhanced to be able use their full power. This power also enables you to be a worthy vessel able to handle the stress that comes with powerful quirks.
Project V17/Powers/Shardless/Physical Powers/Body Modification (My Hero Acadamia)
From Worm CYOA Wiki
Quirk Singularity Theory
Due to both the modifications to your body and the quirks you hold your body has begun to change and mutate trying to adapt to the quirks you hold and the environmental factors around it. You are now capable of growing and retracting mass amounts of limbs and flesh as you would easily hair, nails or skin, adapt to deal with new threats and so on.