If there is one thing Russia does well, it's play the long game. I think a lot of their aggression is meant to cause a demographic shift over time. There are already about 1 million Ukrainian refugees living in Poland and Slovakia, and I think that is part of their strategy. Chase Ukrainians out and move Russians in, then over time, you take the country without a fight. Putin is just trying to find that line where he can do this quickly while still making it unlikely the West will do anything other than bark. It also has the added benefit of causing economic hardship on neighboring countries that they see as unfriendly.
In related news, Czechia expelled 18 Russian diplomats and said they have evidence that the 2014 explosion of an arm's depot that killed 2 people was an act of terrorism sponsored by Russia.
https://www.rferl.org/a/czech-republ.../31213592.html