I think at this point it is safe to say most historians are comfortable using the 'G' word to describe post-1492, and even popular understanding is finally moving in that direction. But something I have seen is debate and discussion as to whether it is better to describe is as one, ongoing genocide, or better to talk about there being many different genocides.
Not being plugged into the issue enough, I can see utility in both, and possibly even they are more complementary frameworks rather than opposing ones, but you know what they say about assumptions.
So the sum of it is that I would certainly be interested in better understanding what this discussion looks like, the direction it is going, and what we can learn from the different approaches, both in the academy, but also within indigenous communities and how they specifically use the concepts to approach their own history.
I am not of an American Indigenous community, and thus cannot speak to your last two questions except by what conversations I have had with community members. I can speak to the direction the academy is heading, however, although my focus is centrally on North American Indigenous groups.
My last qualifier -- that I focus on North American Indigenous groups -- belies the quickest answer to this question: genocides, plural, is usually necessary because American Indigenous communities are not one people and experienced / navigated policies of termination in markedly different ways. This is particularly true of North/South/Central America; to my understanding, historians who focus on Central/South America, are actively in discussion over whether the lens of settler colonialism is properly applied in the region at all. (Although scholars like Shannon Speed, 2017, firmly locate settler colonialism in Latin America.)
As you touch on, plural genocides (or 'fractal' massacres that constitute genocide, as Barbara Alice Mann, 2013, argues) and a singular, broad genocide are not always in conflict. But many tribal histories published in the last ten years focus on the navigations of genocidal policies within a specific community, as the worldviews and historical perspectives of specific communities affect that navigation. For example, Joshua Reid (2015) emphasizes how Makahs used their ability to control maritime space and access to resources in order to resist settler dispossession. On the opposite coast, Malinda Lowery (2018) argues that individual Lumbee's land ownership helped facilitate this survival.
These histories nevertheless tie specific tribal experience to broader histories of Indigenous dispossession. We might see this move as mirrored by academic publishing interest, with the relatively recent rise and popularity of NAISA (Native American and Indigenous Studies Association) and their NAIS journal as committed to engaging broadly conceived Indigenous experiences in one place. Historians who look at Indigenous boarding schools and residential schools (who sometimes label these institutions of genocide as well), or scholars who study Urban Indigenous peoples will often note that, when Indigenous people of varying backgrounds are in close proximity, it is difficult not to note overlapping experiences of genocide and dispossession. (This, of course, is just one theme in this body of work. I'm skimming over some complexities.) These experiences can't be copy/pasted onto other groups, but connections can strengthen unity across individuals and nations.
Finally, to your last point -- the community I work with is perfectly versed at using 'genocide' to describe their histories, and they were quick to correct me when I waffled. They rightfully see themselves and their kin as survivors of genocide, and their survival and resistance (survivance, per Gerald Vizenor) is continually remarkable.