Allowing Ukraine to join NATO is akin to pulling the pin on a grenade and waiting to see what happens. The threat of Ukraine’s admittance to NATO was one of the stated reasons that prompted Russia to invade Ukraine. Pro war advocates claimed this was nonsense and there was no plan to admit Ukraine into NATO. That claim was dubious at best.
Still, if there were discussions and negotiations taking place regarding Ukraine’s admittance into NATO, that discussion ended when Russia invaded Ukraine. If Ukraine’s admittance into NATO was one of the issues that caused the war to begin, threats to allow admittance would only prolong the war or end any future peace treaties. It became a moot point.