wait if sukuna is in his original body, doesn’t that mean megumi’s body no longer exis...

Well Sukuna wants like that from a beginning with Yuji remember? He wanted FULL control but since he couldn’t do that with Yuji added that Sukuna saw him as “uninteresting” he probably did all that towards Megumi to be so depressed that Sukuna can be in control.

That’s what demons usually do, they make their victims feel negative and vulnerable to make it easier for the demons to remain inside their victims. Btw, I know Sukuna is a curse, not a demon, but same thing.

I think Megumi is likely alive but trapped within Sukuna’s overbearing presence.