I think that, at some point, there may well be people in the Russian government and military who will ultimately give Putin a come-to-Jesus talk that he will actually listen to. The trick will be to find a way to pull out of Ukraine but be able to claim some sort of victory.
@DunningKruger a part of me truly believes that the reason Zelinsky stayed in Ukraine so long was because he was hoping the Russians would kill him, declare victory, and leave.