tbf, there is a bit more than that.
The Maidan movement might have had public support, but behind the scenes EU and US actors were definitely jockeying to choose who to support. There are documents and even intercepts showing that. And after the world stopped caring, the new regime turned out to be not particularly less corrupt than the previous one - hence Ukrainians voting in complete outsiders like Klitschko (a boxer) and Zelenskiy (a tv comedian), who in turn sold out very quickly too to various interests. Zelenksiy is balls-out pro-NATO, but without this war he risked being thrown out, after his offshore funds were found in one of the various PanamaPapers-like leaks. He managed to lose pretty much all political capital and support he had in a matter of months, and his Nato obsession was seen as a bit humiliating really.
> NATO explicitly mentioned that no countries are allowed that have border disputes, that's why Russia started a gray zone war immediately after in 2014.
That has more to do with those regions being largely Russophone, and the Ukrainian government being too weak to regain control over them. If that was the only obstacle to join the Alliance, don't you think Zelenskiy or his predecessors would have just renounced them? Surely that's a price worth paying for a permanent security upgrade for the rest of the country.
No, the reality is that even the alliance never really wanted Ukraine to join. There are already enough members to contain Russia militarily if needs be. Same goes for the EU, which is already pretty big with 27 members and stalling pretty much all requests for further accession (not just Ukraine but Serbia and others too). But dangling carrots in front of people is how you make them do your bidding, so such requests are never formally rejected, just stalled forever.
> Ukrainians wanted deeper ties with Europe
Putin likely doesn't care about that, he cares about the leverage Ukrainians have over the precious Gazprom product that helps him stay in power.