Russia wants to end NATO without going to war with NATO.

NATO's political unity and ability to respond is tested with these attacks. Russia does them one after another gradually escalating. Russia maintains plausible deniability or does so small operations that they can always walk them back.

Eventually, some country invokes Article 4 or 5 consultations. Russia hopes that US, Hungary, or Germany waters down NATO response. The conflict continues, but between individual countries not under NATO. NATOs as a organization may continue, but raison d'être is gone.