For me, tapping Share pops up a toast message saying "Copied results to clipboard", and then I go to my family group messaging thread and paste the results. I know that it's possible to invoke the native share dialogue because Reddit does it, but for me, Wordle does not.

Firefox on Android.

Same for me, Chrome on Windows 11.

Sounds like Firefox hasn't implemented the API. No surprise, Firefox is always miles behind on stuff users actually want. It works with the native share box on Edge Android.

You misunderstand. Firefox has implemented the API, because it works on Reddit and other websites.