I don't know if it is whataboutism. If the rich lawyer complains, is it whataboutism to point out worse suffering? It seems to me that Warren Buffett could refuse to do philanthropy on the grounds that he has much less money than Gates and any argument against his position could be said to be whataboutism if you are right on this.
My understanding of whataboutism is that it must be an attempt to deflect from some problem that the user doesn't want to address. Like if one is a racist and say 'oh but what about children in country X'. And even then, there are ways to interpret what I just wrote unfavorably due to the plethora of possible definitions of the * isms (is it subtle bias or is it fear/hate of, or etc.).
Anyway, the point I would make is that I think your argument about what to prioritize is shaped around the conclusion you want to reach. Consider this: why should I prioritize my fellow countrymen/westerners of another race over my fellow human beings from another country?
Because they are closer or more akin to me? If so, why not care about people even closer to me: my family and my 'tribe'?
What I'm describing is what is generally seen as conservatism and I expect that it is even seen as either actual bigotry/racism/etc or at least related to it, yet your argument for the 'opposite side' is very similar. Or, if you prefer, what might be said to be racist about an argument against caring for other races could be said to be xenophobic about yours, in a way (I'm not trying to insult you, but rather trying to point out a case of repugnant conclusion).
But anyway, the whole topic is vast and I realize that I've contradicted my own recommendation of emphasizing solutions, so here is my attempt at that: it could be that there are ways to improve race relations that are either the most effective ways to improve the world or that also happen to benefit everyone's ingroup and if those exist then I encourage people to focus on sharing those.
As for more contentious solutions, I have no idea yet. I have seen too many life skill assessment surveys and such to believe that pure 'system 2' solutions (to use Kanehman's nomenclature) will ever work: most people are what Kahneman would call 'lazy thinkers' and I'm fairly convinced that the *isms are merely consequences of such cognitive biases. Short of genetic engineering or separating groups into nations based on their group identity, I don't know what could work.