NATO and the EU did not show up at their doorsteps. Baltic and Eastern European states willingly joined NATO and the EU seeking better economic opportunities than what they had under Russian imposed communism and protection against future Russian aggression.

NATO didn't invade those countries under special military operations but those countries joined willingly since it was in their best interest and despite the EU's and NATO's faults, they're better alternatives than living in the fear of Russian aggression where the sate can imprison you for saying stuff against state approved propaganda and living in constant poverty and corruption.

Eastern Europe has ~50 years worth of scars to prove how vile such regimes were. That's why they were so eager to join NATO and the EU at the first chance they got and they flourished quiet well after that economically and socially. And Ukrainians wanted the same for their country since 2014, not living as Russia's puppet state forever.