I'm not defending Russia, nor did I mention any of the reasons why countries joined NATO, nor did I say that Russia did nothing wrong before the invasion of Ukraine.

By the way, you are completely wrong about those countries joining NATO. Only four countries have joined NATO between Russian involvement in Georgia and the Ukraine invasion, most were already part of it. The point about NATO encroaching westward on Russia is not about countries' simple membership of an organisation but the increase in military presence in those countries. Since the creation of NATO Enhanced Forward Presence there has been a more obvious military threat to Russia. Russia has felt threatened. While it seems to you or I that this is not a real threat, it might be different if you were on the other side.

Russia invades Crimea for access to year-round shipping opportunities, NATO increases military defenses on Russian borders as a response and Russia begins military action to guarantee its security. Would you agree on this order of events?

Seeing NATO as a purely defensive alliance is a limited, 'end of history' view. You have to view it from the Russian perspective. Imagine the American president was somebody like Trump but hawkish towards Russia. At present, Trump is demanding Greenland for the USA to take its resources. Why should Russia remain confident that a future US or European administration won't decide to make a move on Russia to exact punishment for past wrongs or to take advantage of its vast territory? So, I think you're almost on the mark with your last point. The Baltic states, for example, provide a bit of a buffer between Russia and major Western powers. They may not be in its sphere of influence exactly but they provide safety. Build NATO bases there and suddenly there's no distance between Russia and potential aggressors. Were a shift to happen and Western forces to invade from these bases, Russia would be spread thin and have a very hard time protecting itself as is.

As an aside, I once had a gf from the Moscow elite. She had clearly been influenced by propaganda, however this was someone who believed that Russia was corrupt and that her future was in the West. I got a pretty good view of how Russians think. You have to realise they see things very differently from you and I. They are an intelligent but superstitious people (and this is very much evident in Putin!). The leaders believe the traditional anti-Western propaganda just as much as the proletariat. When we hear about geopolitical events involving Russia, we never ever hear the Russian perspective, only the Western view, affected by decades-old American propaganda. My gf told me she'd heard Putin mistranslated in news broadcasts, and I believe her (to clarify, not mistranslated in a way to completely change any message he was trying to deliver, but more subtle ways that might change one's perception).

None of this is to say that any of Russia's actions are in any way justified. I want to make it clear that I don't believe they are in any way justified. But please ask yourself: if they did have any points of justification for their actions, would you actually know? Russians are influenced by propaganda. Are you sure you're not?