As Apple has been steering people away from custom URI schemes, I doubt they will ever support platform-level dialogs for the user to select an app or a system wide 'open in' default.
Coincidentally, the methods used for this today in macOS (in apps that prompt to set themselves as the defaults, or populate a drop-down) are deprecated.
Coincidentally, the methods used for this today in macOS (in apps that prompt to set themselves as the defaults, or populate a drop-down) are deprecated.