I wouldn't characterize Signal as "absolute most possible safety" as you are implicitly doing here.

I would probably characterize Signal as "most possible safety for the average nontechnical user" which entails trade-offs against absolute safety for certain UX affordances (and project governance structures that allow for these decisions to be made), because if said affordances are not given, the average nontechnical user either simply won't use Signal or will accidentally end up making themselves even less secure.

I couldn't be less interested in arguing with you about Signal. My point is that it doesn't make as much sense to compare Signal and Matrix as people think it does. Large-scale group chat is intrinsically less safe than the kind of chats most people use Signal for. You can substitute whichever other secure messenger you prefer.

This "average nontechnical user" stuff, though, miss me with. For 2 decades people have been encouraging the "average nontechnical user" to do incredibly unsafe things on the premise that any kind of message encryption is the best alternative to sending plaintext messages. No: telling people not to send those kinds of messages at all, unless you're dead certain the channel they're using is safe, is the only responsible recommendation.

This is basically the same logic for why I often recommend Plex over jellyfin to people. Yes Plex is not proper self hosting. Yes Plex the org is making increasingly questionable decisions. But for people who want to get away from the major streaming services and maybe even want to dip their toes into something that resembles self hosting, there really is no other option like Plex. It’s so insanely turnkey and easy to install on every device. You also don’t have to worry about exposing your network if you don’t know what you’re doing.

If nothing else it’s an incredible foot in the door for a lot of people to make the leap to something like jellyfin later.