What this nigga >>64455590 said. Most people in "the west" don't understand the real motivations behind the war. It's not about Donbas, Crimea or even NATO. It's about Ukraine existing as an independent country, separate from russia. The imperial mythos can't stand that organically, since it pisses in the face of the fake russian history, culture and worldview. It would be less of a pressing issue if Ukraine was Belarus 2.0, existing independently only nominally and being fully under its thumb. Or if Ukraine collapsed into Georgia 2.0 after the 2014 shitfest. But nope, somehow those pesky khokhols had the nerve to fight back.
Why is that so important? Because russia doesn't view 1991 collapse of USSR as "the fucked up soviet empire collapsed, now we can be a normal country", but as a temporary embarrassment. They want "their stuff" (what they delusionally view as "their stuff") back. Ukraine is the biggest corner stone of that. They want the whole thing lost in 1991 back, yes, and yes that includes the Baltics. That's why even during the 90s, when they were FUBAR from the point view of both economy, military and society, yet they chose to engage in destroying Chechnya to the ground (including fucked up bombings, killing civilians and everything else) just to stop any movement for autonomy or independence. Because of reasons. One of them is their own "domino theory", as in "if people want to rule themselves, our empire collapses piece by piece". But Baltics isn't that big of a pain point for them at this point, it can wait with them, while ukies are more or less the pic related.
There's also the issue of ukies becoming an example of alternative model of life for the population of russia. It already was low-key the issue, with the people from Belgorod traveling to Kharkiv for things and seeing just how better life can be when the imperial center doesn't rob the province to the ground. Can't allow that. People might start asking question.