As I understand it, these kind of applications depend on being able to perform activities in the background, which is highly limited in iOS for battery efficiency reasons–and maybe for privacy.

Many years ago I was working on a project that shared connectivity details over wifi/bt, and iOS was troublesome also due to the application not being aware of the local bluetooth address.

Possibly similar issues impact other mesh networking applications on the platform.

Another way to check is to

strace cp testfile testfile2

and the sequence in which the message is printed and operations performed can be studied.

It’s perhaps a lot to read, but linux tracing tools are worth learning!