Yes, yes, I know the U.K. likes to use the word "ethnicity" to stand in for the word "race" with approximately zero substantive differences between the meanings. That doesn't make the categorization any more enlightened. It's equally rubbish.

Look at their ethnicity bar graph here: https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationestimates/articles/populationestimatesbyethnicgroupandreligionenglandandwales/2019

Tell me, what ethnicity is "Black / African / Carribean / Black British", hm?

Clearly all one, or at most four things, right? Or, well, maybe dozens to hundreds in Africa alone: https://en.wikipedia.org/wiki/List_of_ethnic_groups_of_Africa

Do we need to get into the profound cultural and linguistic differences between people in Africa to notice that, huh, dumping them all into one bin--makes pretty much zero cultural sense, zero linguistic sense, and zero genetic sense? The only sense it makes is "well, kinda similar skin color same continent of origin, at least partly I guess, and HEY it matches what we're supposed to do for 'race'"!

I can't even tell if you believe what you're saying, but if you do, you need to read more.

Same grouping, different name, no difference in meaning. You might want to collect the data to help you assess impacts of current and historical discrimination (which is based on "race" or "ethnicity as another name for race"), or you might not.

But the only reason to use one word over the other is what the target audience is more likely to understand. The widely-understood not-particularly-sensible groupings are fully adequate for the point I'm trying to make.

Maybe you can tell me, based on the example historical figure I chose, which target audience I was writing for.