Putin knows that in an election year, figuring, most likely Biden isn’t going to risk any pre-emptive military action (even with congress approval) to oppose Russia. If they do attack, Most likely, Russia is going to roll through, establish naval bases on the Black Sea, and park military formations on the Polish border. A dramatically more dangerous security situation.
It's also possible in 2024 Russia could get a Republican president who is willing to say “you know what, fuck NATO, just help yourself to whatever seems fair.” American politics isn’t the center of everything, but I have to think it may factor into this situation to some extent.