Depends on who can control the media and the military. The first few are probably not going to last too long because of the shitastic economy they're going to inherit. Ukraine could get worse if they see it as necessary to prove themselves/distract from the economy or they could pull out so they can consolidate domestics affairs first.

I imagine the immediate successor will be in a pretty shitty spot. Putin has been redlining the Russian economy for years on this personal strongman war. To my knowledge the whole operation is held together by his coercion and cult of personality.

I'll be curious to see if Putin's foreign agents remain loyal. I get the impression that Trump and other puppets are directly in Putin's orbit and might be less likely to attach themselves to a Russia in tumult.