The only offering for p2p support on iOS that I’m aware of is the MultipeerConnectivity framework. Based on its documentation, it only seems to support nearby devices (ref: https://developer.apple.com/documentation/multipeerconnectivity).
Now, by “truly decentralised”, I mean no use of a backend whatsoever.
Perhaps there’s something I might be missing. If wallet apps are indeed, truly decentralised, how do they achieve this?