There is a reason why we established a rule-based order in 1945, even though it has been far from perfect. The United Nations, especially the UNSC, are heavily flawed. In many if not most cases, where decisive questions were asked, the UNSC has been proven useless, and even when UN resolutions passed, they were frequently just ink on paper.
Yet, there were some universal rules which all sides have abided, because they were too much, even for this flawed system. Not changing borders by force and annexation of neighboring territories were some of them, especially by a nuclear power. Russia grossly violated this universal rule back in 2014 and the world stayed basically silent, inevitably leading to the events starting 2022. If not corrected it will launch a process which cannot be reversed. Countries across the globe will acquire nuclear weapons, because it is virtually the only effective mean to counter an aggressive neighbor. Ukraine might be the first country to do so, for good reason, but it certainly wouldn’t be the last.
Dozens of countries are just waiting and watching how the events will unfold in Ukraine. If Russia can get away with it, even partially, then all dams would break. It would be without any hyperbole the most consequential developments of our times, including all unpredictable consequences. No Isolationist country or government on this planet would be immune from those events. We are all into this.