OK, what has Putin done in nearly 25 years in power to lead you to that conclusion? Where do you think Putin would "expand" to next if Ukraine had been a pushover?

I agree that invading Ukraine was wrong. Seeing the situation, I understand why Russia did it, even if I think it was wrong.

The war in Ukraine is expressly because of NATO expansion, and NATO is the European front for US foreign policy. The US is explicitly behind the (openly stated by high US political and military figures) a proxy war between the US and Russia. Therefore in any discussion of the war in Ukraine, US empire expansion through NATO is intrinsically intertwined.

Russia and Ukraine got along fine as neighbors from 1991 until the US-backed coup in 2014, after a similar but less violent and overt attempt in 2004 failed.

Russia explicitly stated (see the leaked Burns Memo from 2008 "Nyet means Nyet") that they wanted to avoid exactly the situation that the US engineered in Ukraine, because Russia said - again explicitly - that they knew a split in Ukraine could lead to civil war, and then the Russian government would be under extreme domestic pressure to join the fight to save the ethnic Russians in the east of the country.

It was US meddling in Ukrainian elections that lead to the coup in 2014 that then lead (multiple very important steps I'm leaving out) to the Russian invasion.

The point of all of this is that if Putin was really expansionist, he would have annexed the Donbas in 2014 when those two Oblasts explicitly asked Russia to take them in. Russia refused. Ukraine was MUCH weaker as a military power in 2014.