I should add that Russia desires the Baltics, which are in an awkward position to defend by NATO. Finland has a strong military and its proximity to those countries makes an incursion somewhat less likely.
Indeed they demonstrated that, but don't underestimate the effect an existential crisis like this has. We will almost certainly see heavy changes coming to the Russian military. It could be that in five to ten years their military is actually capable, after both structural and strategical upgrades.
And the lines we now draw between NATO, Russia and China could well be the lines of a WW3 within a decade. Hopefully not though.
The more NATO expands, the higher the risk of that war. Russia joining China wasn't even a foregone conclusion, but our leaders are doing everything they can to push it in that direction.