The operative words here are ‘likely’, ‘unlikely’ and ‘probably’, which function as verbal CYA for a retired general giving an over-simplified analysis based on insufficient background knowledge.

There is pretty good consensus around not joining NATO while you’re in a territorial dispute.

Which is one reason why Russia love to maintain low-intensity border conflicts with non-NATO member countries, just to keep them out of NATO. Russia is gaming that rule to the extent that the world might actually be a more peaceful place if NATO scrapped that rule and allowed new members with a border conflict.