Tired of the neocon line that Russia is the one on offense. Given the corruption of Ukraine and its Biden Crime Family handlers, Russia probably feels that the failed state of Ukraine may strike first.
Russians invaded Ukraine in 2014. The war has continued nonstop.
https://en.wikipedia.org/wiki/Russo-Ukrainian_War
Russia also has a legitimate concern about possibly unfriendly countries being right on their border. For example, the Baltic States now belong to NATO.
Back in the early 1960s the United States got all worked up about Soviet influence in our back yard (Cuba). And now we wonder why Russia feels the same about the Ukraine.
America ingested a cancer when the CIA organized the 2014 color revolution. On one hand, it turned Russia into an enemy, just as if China were on the Mexican border trying to flip Texas. But also, it corrupted the US body politic. Everything from Hillary's server, to the fake Steele Dossier, to Biden's corruption, to the impeachment of Trump had roots in Ukraine.
The Ukrainian government have backed themselves into a corner and don't have enough gas/other fuel to get through the winter. They are looking at an uprising in the worse case or being tossed out of power in the best case.