But at least naively, these all seem like the least concern: Fairly well behaved nutrient stuff like phosphate rock, nitrates, sulfur, etc.; while all the concerning compounds are synthetic or semisynthetic (besides arsenic lead etc. which have been out of use for a long time right?!)

AFAIK there is no natural source for most of the concerning pesticides/herbicides like glyphosate, chlormequat, paraquat, aminopyralid, maybe synthetic/semisynthetic pyrethrenoids etc. while the much smaller list of "natural" pestidides (pyrethrum, any others?) aren't concerning because they degrade quickly etc.

But I'm also assuming here that "approved for organic use" means "the substance can be trivially extracted from natural sources" which might not be true