You still refuse to accept that if Putin thought that the remote possibility of Ukraine becoming a NATO member was a threat, the same "threat" to Russia already existed because Estonia, Latvia and Lithuania WERE NATO members, and therefore a threat.
The fact that he didn't invade those 3 "threatening" countries gives the lie to his "reason" for invading Ukraine. If he "drew a distinct line in the sand with regards Ukraine" it was for some other reason, as Ukraine was not and never could be a threat to Russia.
The fact that Ukraine has "an openly anti Russian president" is irrelevant. Do you believe all European countries' leaders are Putin lovers?