I can't believe I'm actually saying this... and this isn't even agenda speaking.
Just entertaining the possibility.
We know Gege subverts a lot of tropes for a shonen manga...
What if Sukuna doesn't lose? What if he straight up wins and just creates his ideal world? His ideals are constantly reinforced as correct in the story, and his character is essentially a meta representation of those things. By him winning it would literally be a direct meta-response to shonen of the last 2 decades