Expecting Unicode to contain a codepoint for every single rendering variation

It's not just rendering variations. While they are etymlogically related they are made with different strokes and are incorrect to substitute for one another.

Technically Unicode has a variant selector that can be used for selecting between variations of the characters, but this does not have sufficient adoption. So that means pretty much everything has to annotate what language it is written in so it can be rendered correctly, else the system has to check the system settings to guess what language the user likely wants to see things rendered as.