That’s not (necessarily) the case.
Maybe this gives you a better idea about the global elements:
You are basically styling the tags, with the ability to add classes in some instances, for a more granular control by adding specificity.
For me, global elements have the single purpose of basic general/global styling, just like setting up my headings (h1-h6).
Again, you are not styling classes, even if you add them inside your global elements.
I think what you described is clearly a case for global classes.
At least, that’s the route I’d choose - especially from the perspective of flexibility and best practice.