we should see African subpopulations (given the large number of distinct genetic populations) with higher IQs than white people.

A few points here:

• we already know European and East Asian populations are probably the smartest genetically because they are the smartest now phenotypically; this has already been conditioned on, so it's illogical to say 'well, we should expect an African subpopulation to be higher'. The race has already been run and the first and second place prizes handed out, it makes no sense to say 'there were a lot of other runners so maybe one of them is in first place'.
• the jury is still out on whether some African subpopulations might approach European/East Asian genetic levels. There is already a wide spread of per capita incomes there. African immigrants to the USA perform famously better than the native Africa-American population, and we don't know if this is solely due to a migrant selection effect. Nigerians in particular seem to do well, IIRC. (Piffer's results don't indicate any African subpopulations like this, but I have a lot of doubts about the method and whether he has enough SNPs or reference genomes to rule out sampling error and systematic biases.)
• African subpopulations could be expected to be more closely related than to Europeans or Eastern Europeans, reducing the variability
• and of course, selection cannot be ruled out. Selection is pretty important because we still need to explain why intelligence, which is so useful, has not been driven to fixation, and some of the older theories like mutation load are dead in the water, leaving only a few viable theories like balancing selection, which would directly imply that different genetic levels are due to tradeoffs for metabolic resources or faster lifecycles.

The worst occurrence did, yes.

WP says 30-70% is the usual range, but all of the majority percentages are isolated to small area or are urban areas which make up only a small fraction of national populations in that time period & would be expected to have much higher mortality due to density. In any case, even if the Black Death did kill 70% of the population, one event cannot compare to many millennia of constant disease burden in selection power.

Except we're not talking about one white population and one black population, but dozens of each.

That makes your point worse, not better. The more subpopulations, the smaller each on average and the more powerful drift is, and the larger the spread of extremes. The maximal point drawn out of 2 samples with small variance is smaller than drawn out of dozens of samples with a larger variance. (Also relevant to embryo selection: the more embryos you generate, the better your chance of getting an unusually high scoring one to choose. Diminishing returns, of course, but still large increases initially; the equations & simulations are included in my embryo selection essay.)

Ah. No. After the first few just-so stories based on armchair philosophy while deliberately ignoring half the studies out there in a deeply conflicted field of study, I got bored with the topic.

I see. In any case, I'm glad to see that based on your replies so far, you've abandoned your position that 'the truth of HBD cannot matter' and are settling for arguing 'HBD is false'.