It's great as long as you can guarantee that the person you're communicating on the receiving side does the same. Otherwise it's useless as your messages will be read on the receiving device. In practice it will make private communication extremely cumbersome and niche.

Also, the authorities can backdoor your custom ROM device at will, when seized.

Custom roms is your best bed

Didn't know they come with sleeping facilities. They're so versatile nowadays! SCNR

They will begin so, but the regulation means the authorities can backdoor your device way easier than they can today. It doesn't mean your custom ROM device will be free of the scanning software forever.

It also means that you need to know that the receiving device you're communicating with is clean custom ROM device, otherwise your messages will be scanned on the receiving side.

The regulation is a complete shitshow privacy nightmare hiding under CSAM trenchcoat. We'd do well to organize and fight against it, instead of trying to back down to the perceived safety of esoteric custom ROMs.

Europe: Companies can't lock down your operating system.

Also Europe: Companies must force back doors into their operating systems.

I wonder how long those two things can coexist.

Yes, but not everyone they want to talk to will go through that effort. It's already hard enough to convince someone to download another messaging app that they will only use with you.

"privacy enthusiasts" not everybody can do that. also remember that privacy is a spectrum.

If you are running Android Open Source Project without Google Play Services, Google has no control. However, manufacturers could be pressured into locking bootloaders and then no one gets AOSP or GrapheneOS at all.