I may (and I most likely will) be wrong, but I guess it's actually too late for Sukuna.
All the path toward afterlife stuff can't be purposeless.
Imo Yuji already has Sukuna's fate in his hands.
He just gave him an opportunity to go north after his death.
But Sukuna, as expected, chose south.
In this case, no matter what he'll do. It's too late.
Opening his DE wont change anything. We could have a panel in which, after opening it, Yuji will swap his place with Sukuna's, turning his demonic hostel into a benevolent buddhist deity one.
Sukuna's fate will be the same as Mahito's, but even more tragic.