"after russia invaded in 2014": Crimea was taken away, this yes, while the uprise in Donbass was, as far as I know, spontaneous, with tacit Russian support; both followed the coup organized by the west in Kiev (there is no doubt about this, it was an unconstitutional coup, and the west did breach an agreement - tacit perhaps, I don't recall - with Russia as Lavrov stated).
"Maybe you got cause and effect mixed up here?" - telegram channels calling to kill all russians did indeed appear after February 2022, or at least I think so.
As for ukranian nationalism, it was encouraged by the west, with end purpose to get NATO to Russia borders. You see, contrary to what americans would like to believe, there is nothing truly exceptional about your democracy. Though there are substantial differences between Athenian democracy and what you call democracy, its way to expand by luring the people governed by oligarchies with "people's government", disrupting existing order, causing chaos, war and misery - at least until it substitutes the existing oligarchies with "people's" oligarchies, is unchanged for at least 2400 years (you can try to read, if you have not read them before, Thucydides and Machiavelli's "History of Florence", preferably older translations where they do not translate "demos" as "democrats", I have seen also this lately).
"That is just a weak reason to reestablish a russian empire. And that's the main thing here happening, for some reason Ukraine does not want to be part of your empire anymore and you try to force them." - in a recent book ("Occidente e il nemico permanente") by Elena Basile, an Italian ex diplomat, she states that all of this would never happen if the west had not turned Ukraine into an anti Russian state (I would cite more, but I don't have a time to look this up). She is not a Russian propagandist, but just a person trying to reason by herself given the sources available, as so many people whose voices get silenced in the west under the pretext of "Russian propaganda", while she calls for mutual tolerance and respect of rights. (And of course there are many other examples besides her.)