It's the same thing with Russia: Putin has struck a deal with Xi that allows him to move his military assets from the east to this theater, because he feels that it's a strategic imperative to 'clear the neighborhood'.
Russia has given up land and trapped foreign invaders, including Napoleon and Hitler, but it has done so at a huge cost in blood and treasure. From Russia's perspective, it's far more cost-effective to have weak client states that do their bidding on their hard-to-defend flanks, than to have strong, democratic, independent states that can ally themselves with their archenemies.
Might as well start preparing for the Mexican invasion of the United States.
Since my nation was literally behind the Iron Curtain, I can assure you that Russia _has no right_ to invade neighbouring sovereign nations, no matter how "unsafe" they are feeling. Invading Ukraine is an attempt to externalise the cost of having a land buffer, by stealing said land from a nearby nation.
No matter how "cost effective" it is, it has a real price in human blood and suffering. Only a sociopath would agree it's a reasonable solution, if one were to be (or pretend to be) a good-faith geopolitical player. Which is the current perception of the Western stance on the NATO-Russia tensions from the perspective of ~everyone who cares about human rights and the right to national and personal self-determination.
That's not terribly different from what Russia is doing with Ukraine - they will overwhelm a weaker country for their own strategic reasons, enjoying the impunity granted by a nuclear arsenal (and not just your average one: the largest!).
Russia wasn't forced to do anything. They could've merely quietly dropped two of their delusions:
a) NATO was never going to attack them, unless it literally went crazy, or someone framed Russia so badly that a nuclear response was preferable to any other option. The West doesn't want to trigger a MAD scenario, and are keen to keep the post-WW2 peace and (in the case of the US) bomb less defended countries for their natural resources. Any claims or beliefs to the contrary are a projected reflection of their own priorities.
b) buffer zones outside of the neighborhood is getting more crowded. Big deal, if you are really so keen on a buffer zone, then maybe sacrifice a few square km out of the ABSOLUTELY MASSIVE part of the continent that they already control. Does that mean risking important areas? Oh noes. Security has a cost, so if you're not willing to pay for it, quit whining.