It’s tricky, because there are definitely ways to erase a culture/civilization without mass killing. Combinations of displacement, the sterilization and resource disruption others mentioned, cultural suppression. Although obviously there’s a lot of gray area, especially with the cultural suppression aspect.

However, there’s a difference between the sort of exacting, navel gazing definition we can come up with, and what the immediate reaction/assumption of the average person is when they hear, there’s a genocide going on over there. Which is to say, they think of the Shoah, genocide means concentration camps with gas chambers. So there’s a problem where, coming up with a broader definition on paper won’t change the reality that it will misrepresent what’s going on to the public.