The short answer to the title of this article is: We may have no choice if the world is to be saved.
I agree that Russia was pushed to the wall (border) by the NATOization of both Western and eventually Eastern Europe, and it was Ukraine's existential threat to join NATO that pushed Russia to respond forcefully. I was one of the few to keep saying that Ukraine had to figure out how to live with its larger, more dangerous neighbor, right up until the moment of the invasion. Like a lot of people, I expected Russia to back down or at least to maintain a border stalemate until a neutralization agreement could be worked out.
I accepted the apparently legitimate vote by the residents of Crimea to join Russia in 2014, though Russia's actions to annex the Donbass and Donetsk regions seemed a bit too far and non-specific geographically to me. In any case, the West should have bargained in good faith with Russia over that conflict and had years to do so.
For that matter, the West is guilty of encouraging looting of Russia in the 1990s when the USSR fell and the Baltic and Stan regions split off into other countries.
OTOH, those countries chose to align themselves with the West increasingly. Why is that? Russia under Yeltsin and especially under Putin, had a chance to foster human rights, to open fair trade with those countries and to negotiate de-militarization with them and the West. Russia did some of that, but still all those countries remained afraid of it. The partial annexations in Georgia and elsewhere reinforced that fear. I recognize Russia's historic relationship, and reliance on, large areas of land as a natural defense, particularly in the west where their capital and most valuable cities are (and particularly in winter). But with air power what it is, land alone was never going to be enough of a buffer for Russia in the modern age, and to expect the breakaway regions to rejoin Russia is ahistoric - i.e. there are about 1/3 more independent countries today than post WWII. This also runs counter to the Western argument that the world is headed for a common Globalized future. That was never the direction of cultures and humanity.
However, when Russia violently invaded Ukraine, the facts on the ground changed radically. Putin miscalculated greatly. Actually, it probably surprised even the Pentagon, NATO, and the governments of the EU how much the people of the West collectively opposed Russia's latest in a long line of takeovers, when little had been said or done before. After all, the world mostly shrugged since 2014 when Russia took over Crimea (including me). But Zelensky wasn't president then and Ukraine was in chaos then, more a threat to itself than Russia was. Quietly, even controversially, Zelensky had been adapting and even incorporating the NAZI forces into the military, both recognized and semi-private, because he needed them to oppose Russia in the East. This actually weakened that resistance to Ukraine's government and ensured they soundly lost major electoral power; it is a particularly "Western" approach to neuter one's enemies and it largely worked. Russia's invasion, which has been hardest of all on the supposedly rebellious regions that Putin allegedly invaded to protect Russian speaking citizens, has shown some of the strongest grassroots resistance, though they are, for now, overwhelmed by Russia's superior forces.
The big question, not just for Ukraine, but the entire world, is whether Russia can achieve enough of what it wants and needs to feel, as Putin has said repeatedly, non-threatened by Ukraine, to make an agreement that Ukraine can also live with. Will there be an agreement? Will Ukraine have to give up the east and possibly even the southeast, which includes most of their Black Sea access. Even Odessa to the southwest has come under fire recently, and it is very unlikely Ukraine will willingly ever give up areas that don't immediately border Russia, not including disputed areas like Crimea. They will not agree to become a land-locked nation under anything like the present conditions. If the West does not/cannot continue to supply Ukraine with weapons and support to at least continue the stalemate, Ukraine will keep fighting to get back its territory.
The big unknown is the big danger, that Russia will employ nuclear or biological weapons.
The former is more likely simply because it is easier to geographically contain, though any fallout would certainly radiate over Europe, NATO territories, and stress Western reaction to the breaking point; it is very hard to imagine that response would NOT lead to WWIII and the possible extinction of most of civilization, though its pretty hard to wipe out 8 billion people all over the globe, at least not immediately. But the near collapse of the global supply chain just from the Covid pandemic should be a warning to how vulnerable the world is to a nuclear war that would be exponentially worse. This ought to keep Putin awake at night, as well as any thinking person. Yet, he has threatened the West with such a response, and the world is actually closer to nuclear confrontation since anytime after the Cuban Missile crisis, ironically the closest analog to the current situation, that time an existential threat to the United States. It is the dangerous height of hypocrisy for America to ignore that lesson of the past now.
No one can reliably predict what will happen. Anyone who says they can is lying to themselves as well as others. The world is hardly ignoring the situation, however guilty it is of ignoring the earlier provocations and unsustainable conditions. But, to paraphrase others, you don't go to war with the world you want, but with the world you have...if you can keep it.