Russia has announced they have the right to expand their borders using aggression. They have committe the supreme international crime, as judged at Nuremberg. If countries aren't subscribing to that world view anymore, then we are lost. We are doomed to have a world war three. The entire fucking point of these institutions is to prevent another one. If nothing else China should be an institutionalist, preserving the international system of laws for its own long term interest.
Maybe it's lost on people, but Poland told NATO in 1993 that if they weren't allowed to join, they were going to build their own nukes. Because they didn't trust Russia. They weren't the only one.
If the U.N. Charter system dissolves, the NPT falls soon after that. And then it's an arms race.
The interested parties in this war are NATO countries and Russia, besides Ukraine, because the war is a consequence of decades of hostilities regarding the re-alignment of the ex-USSR territories East of Poland towards the West and against Russia.