Imo, S4 would only work with a different MC and preferrably a different LI cast too because:
a) The current story is complete, nothing to add, gotta start something new;
b) According to rumours, Lancelot wants to re-capture the spirit of S1 with its carefree chaotic attitude and the inventive fuckfest, but the S1-3 MC has been through too much and got too much character growth to get back there.
So, in a perfect world, S3 gets a DLC where every MG and not just Alice gets the reboot to Thursday and a big, proper ending. After that, if Inceton absolutely have to keep their flagship project afloat, they build S4 around a new cast, with Alice and Carol having to test some new functionality and launching a loop for that. Alice stays in shadows because she might be together with S1-3 MC, but Carol is made fuckable - I've seen some demand for that around. I think it might work, because Lancelot seemingly prefers fuckfest approach rather than story approach, and players who want that are less attached to specific characters and will accept the cast being new if they are hot and represent different kinks.