NATO is spread right across Russia’s western border if you include the unitary state (Belarus).

When Russia started removing the threat from Ukraine, NATO successfully absorbed Finland. I think Russia’s response was “OK, we will take the necessary measures” and they reconstituted some northern guards/tank army in response. It wasn’t a great day for Russia, but Russian concern rises when troops actually move towards the border. This had actually happened in Ukraine, and I recall a quote from early on in the SMO (perhaps from The Saker’s site): If Barbarossa had started from the Donbass instead of western Ukraine, the invading army would have reached Stalingrad in 3 days. [and probably taken Stalingrad given the invading strength]. Instead of > 1 year.

My feeling is that if the NATO-grade army in Donbass had swept up the DNR and LNR in March 2022 as planned, they would likely have swept around and through a slice Russian territory behind the Donbass to complete the encirclement, and also as a humiliation, then kept it as a buffer zone. The immediate threat seems quite compelling. In Finland, there is no such provocation ongoing as far as I am aware, though there will likely be pin pricks in the future.

Hope that helps a bit.

Best regards, Shyaku