This is also another reason why I hate the "population is growing" logic used by some individuals to argue against genocide. The actual official UN definition contains elements that don't hinge on that. It is very much a definition that relies on specific policy actions and intent.
And yes, what Russia is doing in Ukraine is very clearly ethnic cleansing and genocide. Just listen to their own statements.
Russia's mass abduction and indoctrination of Ukrainian children is a textbook case of genocide, according to the UN's 1948 Genocide Convention, which specifically identifies "forcibly transferring children of the group to another group" as an act of genocide.
The “population has grown therefore not ethnic cleansing” argument is a little like denying there’s domestic abuse because the spouse is still alive.