iOS 15 saved this problem completely. ie: the same, identical, app works correctly on iOS15, being able to connect at startup.

Thank you very much for the information, I tried, but it seems not enough... do you have any other (related) keys?btw, mine is a standalone radio application and the name clashes with another radio managed in TuneIN (It seems there is a tuneIN Siri intent manager somewhere, no tunein radio installed here) so I'm not sure it works or not... it is somewhat complex to understand it.

I think this is an Xcode bug. The same error (no distribution profile) now happens also with notarization only (same certificates and profile used another time). If I manually import the profile in the "select certificates and Mac App Store profiles" stage of application upload I import a profile for the iOS/Catalyst app, the process works.On the previous case, improting manually a profile for the app store also continue the process, but the submission is refused because "the app is not sandboxed" (thing of course false, Catalyst apps are sandboxed by default).Anyway, I filed feedback FB7459218 in case someone from Apple is looking at the problem.