Kiev is where Russian nation originated from in the first place. Seizing it is a huge cultural win for him, both in a historical sense and a reunification of former Soviet Bloc countries.
We’ll see, I guess. World is overdue for a large scale conflict. And Putin knows the American people aren’t ready for another war for a country they’ve never heard of (or are tacit supporters of Putin themselves).
Foresight is foggy and hindsight is 20/20.