Confirmed! In Unity 6.5.x, emojis are displayed solid black when using the light theme.
😟
Since this is a Unity bug, I sent them a bug report, and they've logged it in ticket
UUM-147842.
This issue is now officially fixed in Unity 6000.5.9f1 and later. If you're using an older, affected version, switching to the dark theme will allow emojis to display correctly.
I just need to wait for that version Unity to be released and confirm the fix.
After that, I'll close this ticket.
Updated!
Version 6000.5.9f1 was released today. And emojis work without errors! That's absolutely great news! 🤩
Closing the ticket! 😎