NATO expansionism is at the heart of the matter. Russia considers Georgia and Ukraine as "buffer zones" between the West and themselves, by virtue of being next door neighbors. So any attempt to militarize those regions in offering them NATO membership, Russia considers as a direct threat or challenge to its internal security.
To put this in historical perspective, didn't the US also react in similar fashion when Russia established military presence in Cuba which led to the missile crisis in the 60s? Or what if the Chinese decide to establish economic relations with Mexico in exchange for setting up a military presence there, how do you think the Americans will feel and consequently react? The Russians are simply applying their own equivalent of the
U.S. Monroe Doctrine.
I think that the best way forward to de-escalate further tensions is for Ukraine to adopt a similar approach taken by Finland (also a next door neighbor of Russia), which is, to become a member of EU and focus solely on its economic initiatives while maintaining neutrality and no longer pursue NATO membership which will only agitate Russia.
I find Professor John Mearsheimer's viewpoint (
https://www.youtube.com/watch?v=JrMiSQAGOS4 ) on why
Ukraine is more the West's fault (rather than Russia's) to be quite insightful and fully agree with it. If anything, his views seem to have aged frighteningly well considering he made this assessment back in 2015 after Russia's annexation of Crimea. Unfortunately, as he points out, this doesn't seem to be the prevailing conventional wisdom in Washington which poses a real risk of miscalculation. Just because we are in the 21st century it doesn't mean that the rules of balance of power politics no longer apply.
Henry Kissinger seems to share this view as well
https://www.washingtonpost.com/opinions/henry-kissinger-to-settle-the-ukraine-crisis-start-at-the-end/2014/03/05/46dad868-a496-11e3-8466-d34c451760b9_story.htmlThe Chinese are closely paying attention to this not only because are they next door neighbors with Russia, but they also have their own issues with the U.S. with Taiwan.
https://www.ft.com/content/51a61659-8caf-4abc-aca7-4a6808917089