Cascadia Mono/Code Extralight, Light, SemiLight and SemiBold use a fallback font
Here is a demonstration with Cascadia Mono selected:
And here is a demonstration with Cascadia Mono SemiLight selected:
Is there a plugin that lets me load these fonts?
I’ve confirmed in Settings (ms-settings:fonts) that the fonts are installed correctly. It looks like Extralight, Light, SemiLight and SemiBold are some sort of a subset.
I wasn’t able to research this for myself because I don’t know what to call these different typefaces. Like if they are implemented differently, what that implementation is called.
@jacko-png You need to disable DirectWrite to directly use those fonts, but Cascadia Mono (or Cascadia Code with programming ligatures [if DirectWrite is enabled]) will still look much better.