Even Biden never seriously considered regime change as an option — and in any case, the five million-strong security apparatus, the Siloviki, would never allow it. What’s far more likely is that Ukraine, abandoned by most of its allies and largely unfunded, simply collapses. The country is already on life support — if the money stops flowing, salaries go unpaid, pensions dry up, and a whole range of other systems begin to fail. Add to that an armed and angry segment of the population, and you have the perfect storm. That's Putin's endpoint he is aiming for , a client state on his borders and Trump for the most part is happy with that.
https://www.newsweek.com/who-are-siloviki-russias-elite-security-faction-1775796