Actually, it was "proto-EU" who divided Czechoslovakia without Russian permission (and directly against Russian will) And it was lack of European system of equal safety (deliberately destroyed by the UK) which leads to WW2. And, talking about Ukraine, it was Russia, who reunited Ukrainian lands in 1939 by liberation of western Ukraine previously occupied by Poland.
And no, it's not "Ukraine rejected". It's expired dictator Zelenskiy who have no any right to represent Ukrainian people, rejected it. Let's ask Ukrainian people. Open borders, de-fund them, and see - how many citizens of Ukraine eager to die for him.