You can't just analyze this conflict based entirely on events since 2022 when you first started hearing about it in the news. There's a whole half century of events leading up to this, and as of now it's taboo to talk about any of that throughout much of the western world. But by way of linear time, those events are necessary to actually understand what's happening. Otherwise, all you have to go on is propaganda and vibes, and that's what I'm seeing in your two sentence summary.

This is primarily about NATO wanting to encircle Russia, and the card they've chosen to play is using Ukraine as proxy by installing a fascist, rabidly anti-Russian government during the Maidan coup in 2014. Ukraine is not a sovereign state under this coup government. But even if you want to somehow argue they are, if their sovereignty means allowing NATO to militarize one of Russia's largest and most vulnerable land borders with short range nuclear missiles, then it's clearly an existential issue for Russia who has every right to intervene on that.

I'm not going to cry that they broke the Ukraine nuclear disarmament treaty when Ukraine, the US, and NATO as a whole routinely violate every single promise and treaty they've ever made with Russia. In fact, a major condition of the dissolution of the Soviet Union was for NATO to agree they would not continue to expand into the former Eastern Bloc, Ukraine chief among them. Russia tried for far too long to assimilate into the global capitalist system only for the economic and proxy wars to continue and for the encirclement to accelerate, signalling that NATO never had any intention of ever allowing Russia to coexist as a great power on the world stage, regardless of Russia's willingness to liberalize and subject their own people to devastating, crushing, massively deadly austerity during shock therapy.

But also think about how Russia took most of the LPR and DPR in just the first weeks of the war. It's because those areas were already in a civil war against Ukraine. Ukraine has been shelling civilian population centers in the east of the country for years, they were ethnically cleansing Eastern Ukraine of Russian speakers, they have literally banned the Russian language. You can't say "Russia's fault, they invaded first!" when they were joining an existing war on the side of the people Ukraine was trying erase, regardless if that wasn't their only motive.

To their credit, Russia exhausted every diplomatic option they had before NATO had Ukraine abandon all negotiation and peace talks. Ukraine was signatory to the two Minsk agreements in which they promised to cease their ethnic cleansing in the east of the country and accept a ceasefire, but we know now it was entirely in bad faith. They were never intending to follow through with this, rather they were buying time to militarize with the help of NATO.

All this is to say, Russia is clearly not the aggressor here when you look at the actual timeline of events. The story that gets told 24/7 in western news media is blatantly a farce.