But even then...why attack a nato state as oppose to a non-nato state?
Hm, if I was Putin, it would make more sense to bring troops into Armenia, since Armenia is starting to break away from the CSTO. Then attack Georgia (once Ukraine is subjugated, if it is subjugated). If Ukraine is defeated, Moldova won't take much.
That would take some time, and during that time keep working on destroying the EU and NATO from within. Work on Hungary to ensure that if conflict comes, Hungary will sabotage from within - I'm sure that any NATO secrets that Hungary possesses are already in Russian hands.
Try to ensure civil unrest in EU countries; carry on weakening the US from within via social media and, frankly, the Republicans ( :( ) although they might surprise him - I think they have more teeth than he thinks.
Keep China heavily on side, help it also attack the US from within; aim to create distractions in the Pacific.
Work with China to get more unrestricted access to chips etc.
All this gives time to keep building up the Russian forces (and force experienced Ukrainians to fight for them) and vitally to train new recruits. The ones who have survived war so far are battled hardened and effective - we hear a lot about the terrible messups but quietly some pro-Ukraine analysts are also saying that Russian tactics are evolving and improving. Officers who are no longer at the front can train new troops. Won't be perfect, but Russia does seem to rely on brute force as well as training, so it could be enough.
At that point, let the tanks roll into the weakest of the Baltic countries - Lithuania, Latvia or Estonia, NATO or no NATO.
Of course all this depends on them taking over Ukraine.
BUT One thing that will probably send a strong message to Putin to not go too far with NATO is the new NATO base in Romania, which was very much a Soviet state. That could well be seen (and was?) a message to the world that NATO is here and committed to the defense of Europe.