I don’t understand the logic of this. He needs 23 days for the spell to charge and only five hours to do it, so he’s just going to wait in a hyperbolic time chamber? That wouldn’t solve the issue.
@xyzzy
He assumes those hours are his personal time limit, so if he flings himself into the future he can "extend" his own clock by technicality.
The inverse hypothesis is that those five hours were actually that world's time limit and he may have actually rushed into a Game Over.
The time goes faster in that dimension... That's what he explained, with the dude who spent decades in there.
Sekai will spend 5 minutes in there, but when he comes back, 23 days will have passed.
To put it this way: It achieves the exact opposite of his pause button.