Putin could get away with it in Grozny, against Muzzie Chechens, heck most would be rooting for him there.
But Ukraine, the optics matter much more.
Optics and the future. If Putin takes all of Ukraine, their standard of living will improve. A lot by their standards, although not by ours. Bringing median income for Kiev up to Moscow levels would blow them away. I’m no expert on it, but they have minimum salaries in both countries and I think Moscow is like 2 times Ukraine.
Maybe he can win over the Ukrainians. Could be his angle.
Either way, he is gonna get a couple trillion dollars of natural resources at his command.