This is a pretty decent English language history of the area: https://en.m.wikipedia.org/wiki/Black_Sea_(book)

Also, I didn't know about "mova", neat - this language or dialect was spoken in Crimea?

However, leaders of folk movement, later known as Ukrainians, developed and enhanced folk language, which then was renamed into Ukrainian language, and used as one of symbols of independence from Moscow, so it was systematically suppressed by government of Russian Empire, Soviet Union, and Russian Federation.

Crimean Tatars constituted the majority of the population of Crimea before the Russian conquest. They became the minority partly through genocide, and partly because the peninsula was settled by Russian colonists.

Ukrainians, on the other hand, were never indigenous in Crimea. It was not a part of Kievan Rus, so any Ukrainians who lived there, immigrated there after the Russian occupation of it. And there are so few mostly because most immigration to it was orchestrated, and the Imperial government preferred to settle it with Russian rather than Ukrainian colonists.

So in one case, you can talk about genocide of the indigenous population. In the other case, it's preferential treatment of one ethnicity over another for colonization purposes.