The whole point of joining nato (and I don't think it will happen) is to create a deterrent. Russia has historically been a very aggressive neighbour.
I'm pretty convinced that the concept of that deterrent is what has caused the current conflict, no?
Quote
Russia invaded Ukraine in February 2022 after Russia's president, Vladimir Putin, falsely claimed that NATO was using Ukraine to threaten Russia. Ukraine applied for NATO membership in September 2022 after Russia proclaimed it had annexed the country's southeast.
This little google quip is pretty biased, but I feel its a pretty good summary. Though I may be wrong, I haven't deep dived into the history. It is the only thing that really makes sense tbh. Regardless of Ukraine's revolution, its corps and other cultural elements are too tied to Russia. Even if they fully separated, Russia would be able to influence as it did prior. Putting up a front on Russia's boarder by joining Nato is the real casus belli here imo.