If you propose that no material factors inform Putins actions then how do you propose to stop him other than the complete destruction of Putin or even Russia at all? If you think Nato expansion was a factor you already have an avenue to negotiate on for example (al though I think that specific factor is overstated on the left).
To me the war was a result of a capitalism no longer being able to sustain the profit rates the ruling classes needed to keep peace among themselves. So the global and regional powers start to want greater control over its ‘sphere of influence.’ Remember that the first part of this conflict started in 2014 when Ukraine was deciding between a European and Russian aid package. America’s first response immediately folded its narrative of the conflict into the war with China that Washington wants so badly. With this turn to Autarky I at least expect some of the Euro libs to use it as an opportunity to promote a new free trade regime.
In the interwar period the central Europe was carved up after Britain and France stopped underwriting the defense of many countries which led to the carving up of the smaller countries by the larger. To be blunt, these countries were never big enough to be independent. When the USSR dissolved itself the successor state that is Russia was already too impotent to keep central Europe in its influence. My view is that when Russia stabilized and reformed from a super power to a regional one its ambition started out limited enough that the new Nato countries were already considered a lost cause.