Do you know what is actually going on ?
Last week Russian FM Lavrov spoke to a BCC TV reporter : QUOTE But on Thursday, Russian Foreign Minister Sergei Lavrov looked me in the eye and told me things were not as they seemed. "We didn't invade Ukraine," he claimed. "We declared a special military operation because we had absolutely no other way of explaining to the West that dragging Ukraine into NATO was a criminal act." UNQUOTE
If that is the issue then I can assure that EVERY member state of NATO has to accept new members and even the smallest member state has a VETO right / Finland and Sweden applied for NATO membership last May and it could be 2023 before they are accepted. I am sure that most of NATO member states would use their veto to prevent Ukraine's admission because it would be too risky to guarantee protection of a new member which is already in a "special military operation" with Russia.
The abstention of Thailand is understandable because they have no bone in this fight.