>>I did not see this one coming — too much vitamin A

Color me just as surprised. I suspect most people take beta carotene, not vitamin A directly (except maybe in cod liver oil). I got to wondering how well that's converted into vitamin A - and that turns out to have a lot of genetic variability. I also stumbled across xcode.life, which looks interesting... https://www.xcode.life/23andme-raw-data/beta-carotene-conversion-vitamin-a/

TL; DR: there do not seem to be any variants with increased conversion (which might result in having too much A), just normal and reduced ability).