The last thing NATO wants is a fight in the Baltic States, which is why Putin is threatening us there. He looks for a weak spot, and threatening us there. The Baltic States have a dozen obvious choke points for us.
The only reason he is attacking Ukraine and not Baltic States is that attacking the Baltic States would trigger a response from all NATO. If trump had taken us out of NATO, Putin would have been more likely to go after the Baltic States.
Think about it for a moment. The Baltic States were part of the Soviet Union, just like Ukraine. The Baltic States are actual members of the EU and NATO, not just "long term" candidates like Ukraine. The Baltic States are much further along the line that Putin wants to prevent.
And Putin does not limit himself to the Soviet States. He also claims all the Russian Empire, which would include Poland. Poland is both an EU and NATO member. Then there is Germany, never part of the Russian Empire, but Putin points out that it was occupied by the Soviet Union after WWII. We could add on Austria, all the Warsaw Pact, Finland, and on and on.
Ukraine is the thin edge of the wedge.