Earlier quoted context omitted.
This is a little strange to hear, since it's genuinely not possible (as far as I can tell) in the main part of the app . Stories, yes, but not in the feed. It's as if people use these things in wildly divergent ways, I guess.
Good point, I forgot that’s only for stories. The iOS markup editor isn’t nearly as friendly for slapping on emojis and resizing them with two fingers. That said there seem to be various photo editing apps that do make it easier that OP app is competing with.
(My own App Store searching turned up one called Face Blur which seemed to have emoji as an option... as a subscription, which seems like a non-starter.)