Apple should not charge a user for access to their own device. A user has paid for their device in full and should own it. A software company (ProtonMail) wants to sell the user software to use on their device. There is no need for Apple to be in the middle of this transaction, especially at 30% of any money trading hands. I have no problem with Apple charging 30% to be on the AppStore, but vendors should be allowed to install software via 3rd party stores or direct B2C.
This wouldn't be a problem if you could install Firefox, Chrome, etc, but on iOS browsers can't use their engine... they're essentially Safari with a different skin on top.
I think complaints from devs/services make less sense on Android. Almost everyone uses Google's Play Store, but you can install an app manually like you do on your phone or even use a 3rd party store. If you don't like Chrome, you can install Firefox. If Google bans VPNs in China (like Apple did), users can sideload the app.
On iOS, for devs, it's either the App Store and Apple rules or you're out of the platform. For users, it's what Apple allows... and many of their rules aren't there to protect users.
