If he’s doing what the FSB want he liveI see two very big problems with that. Putin cannot afford to walk away with just a sliver of Ukraine in exchange for what they have already lost. If he does, then only a matter of time before he is overthrown. If he doesn't, I see no way out of this for Russia except to off Putin and claim it was all on him. That is the fastest and easiest way for them to recoup their loses, get out of sanctions for the most part, and start working on the corruption that obviously has gutted their military readiness. That is also how Russia has historically conducted business. Just like the mob. Once you make a mistake like this, expect the bullet behind the ear because they don't offer retirement plans. How long will it take the titanic financial losses to get somebody close enough to Putin or will they just finally be bold enough to walk right in and arrest him?
Second, Ukraine has already been burned badly by the Budapest Memorandum giving up their nukes in exchange for phony security agreements. I doubt they have the appetite for that again.
If he’s losing his mind he die
Putin is the front man for the FSB. They run the show not the military. There’s no appetite with the FSB to westernize which is the pressure put by ukraine slipping west. If Putin isn’t deranged or suffering dementia the alternative to him may be worse. There are some serious nuts in government there. Especially the duma. Even Medvedev I do not trust.