Unfortunately, it's on the editor to support mixing fonts. There's never been multiple compatible monospaced fonts before so no editors really support this yet. Lots of editors also don't support variable typefaces properly yet (ahem, VS Code) but this is going to change.
Ultimately what you're describing is the future! But we have to release the typefaces to bootstrap that future.
We made a prototype extension that hack it into VS Code. But they're hacky af and not really releasable.
Emacs and Vim have both supported this since at least last century.
So if I want to use a variable pitch font (like say... DejaVu Sans) to draw comments, I can set the font-lock-comment-face to use the "DejaVu Sans" family.