Other editors/terminal emulators would probably need to add support for this.
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.
Using this approach, you can use up to 4 different fonts: One for normal text, one for italic, one for bold, and one for bold italic. And the font for each group doesn't necessarily need to be that style, e.g. you can use a non-bold version for the `bold` font, etc.
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.
hi Comment guifg=#7e7490 gui=bold,italic
In Kitty, set the desired fonts: font_family IosevkaTerm Nerd Font Mono
italic_font IosevkaTerm Nerd Font Mono
bold_font IosevkaTerm Nerd Font Mono
bold_italic_font Iosevka Term Slab