That is a very common tactic with Russia. Annex land, then forcibly remove the local population and move a bunch of Russians in. Then it becomes easier to claim the “new territory” as filled with Russians.
Again, I think the major distinction is the recognized borders of the territories. Artsakh is internationally recognized as part of Azerbaijan, not Armenia.
Are you confusing something? The 2014 census showed a higher number of Ukrainians than the 2001 one, the Russian part of the population made up a higher percentage because the overall population shrank.
As for the recognition in artsakh: a lot of us states regoznised the territory. I know that the EU did not do it, but - as I have said before- they do not want to anger Azerbaijan as we get a lot of fossils from there. This is why it is hypocritical to ditch Russian gas in favor of Azerbaijan one.