Briar will thrive once EU Chat Control 2.0 passes, P2P E2E encryption is the only way to bypass bullshit laws.
If the goal is messaging that avoids government spying or censorship its a lost cause - the government would simply compel Apple to pull the app in their jurisdiction.
Also, how do you avoid leaking the sender? You can avoid giving Apple that information by routing the notification through a server, but then that server would know the sender and recipient.
"Open source programmers do not understand how to code properly for iOS" != "doing things in the background is IMPOSSIBLE on iOS!!!!!"
People just love to screech about iOS/Apple being evil.
because without such a critical mass of normal users you get something like tor or grapheneos that the state begins to associate with people engaging in unsavoury activity