NATO never promised not to expand:
https://hls.harvard.edu/today/there-was-no-promise-not-to-enlarge-nato/

Ukraine has killed Russians in Dombas since Russia invaded there in 2014 as part of their hybrid warfare campaign, so yes, a long time.

Russia has no interest in fair peace agreements and has said many times internally that Ukraine naturally belongs to Moscow:
https://united24media.com/anti-fake/a-long-history-of-how-russia-systematically-violates-peace-agreements-1471

There is no proof that US intelligence was behind the Maidan revolution in any way.

The last point is true, although the US is not an empire. Ukraine is important to NATO as a buffer zone. If Russia takes Ukraine then they will claim that NATO is aggressing them simply by having existing defenses on their own border.