I've been through the instructions above at least six times, and my app doesn't appear in the share menu.
I suspect in half an hour you might work out what I'm missing and hence what is missing or unclear here, if we could get on a call or something. Then that could be added to this piece and it would be better.
Guyren Howe make sure your Runner & Share Extension minimum App Deployment Target should be same for example if your setting it up Ios 14 then set it for both keep it same also make the MACH-O-TYPE = Executable for both Runner and ShareExtension for it to work in IOS without showing that grey bottomsheet opening and closing issue.