To play the opposite team a bit here, I like the idea Android uses of Intents for something like this. I think it falls apart a bit in reality because app companies kinda want you in their garden and so don’t often do the work to keep things interoperable. That and the use cases from users on phones don’t frequently involve cross app functionality. But the ability is powerful for apps to say “my app needs a user photo” or one of my faves “my app needs a pgp provider (for the password store app)” and then let the other app do that piece of functionality as determined by the OS, which tracks a lot of those providers and lets the user decide which to use.