This year is different than last year. Different variants, different levels of spread. A direct comparison of death numbers makes no sense. Current death numbers of vaccinated people vs unvaccinated people makes more sense.
IIRC a couple places were using vaccines that started out with 3 doses? I don't know. I'm also not sure which countries you're referring to here with the 5 doses, and why it matters. Are you saying that it's inconvenient or expensive enough to get multiple doses that it's not worth the decrease in rates of severe illness?
I mean, lower vaccination rates are one of like 20 differences between Africa and the US. According to at least one thing I read, many African countries had a very aggressive and early lockdown response. The weather's also different, and people are generally younger in Africa than in the US. (Median age in US = 38, median age in Africa = 20.) The difference in death rates between vaccinated and unvaccinated people in the US is a much more compelling statistic than any comparison between the US and Africa.
I'm a little shaky on the details here, but basically all sources I've seen say that vaccinated people are less likely to spread covid. Yes, if Adam is vaccinated and Bob isn't, and they both are currently sick with covid, to the same degree, then it seems like they'll both spread the virus at equal rates, but Adam is much less likely to get as sick as Bob from covid in the first place, so in the absolute he's less likely to spread covid.