The RDA and nutrient recommendations are the bare minimum so you do not die. Vast literature is ad populum fallacy.

Also consider that genetic background matters in nutritional matters and well... The populations under study have changed, and that's assuming you have a fairly similar background to a population and not very mixed.

And we are not even getting into how these things go down in practice, with heavy industry lobbying and what not...

TLDR, you are on your own in terms of optimal nutrition but as another commenter said "eat food, not too much, mostly plants"

They are not, they are recommended averages.

RDA for vitamin C is 60mg, but you can survive without getting sick on 5-15.