I've been inspecting this topic quite a lot and I'm a little confused now. So, we have reasons not to use Signal, reasons not to use Matrix, there were also some claims about Session being a fraught. Briar is mostly activists related (not very suitable for daily use), XMPP lacks good clients and suffers from fragmentation of protocol standards implementation, SimpleX is too feature-incomplete (no UnifiedPush support, big battery drain on Android, very decent desktop client without any message sync). I can't say a lot about Threema or Wire, as I'm not very familiar with them.
So, my question is — is there any good private messenger at all? What do you think is the most acceptable option?
EDIT: In addition to my post:
All messengers have their flaws, I'm well aware of that. I was interested in hearing users' opinions regarding these shortcomings, not in finding the perfect messenger. I may have worded my thoughts incorrectly, sorry for that.
People say this over and over "depends on your threat model" and yet people seem to have a hard time understanding that. Your threat model is "who is your adversary and what he is willing/able to do". Your security goal is what do you want to keep from your adversary.
As others said, if you are an activist or sth important, perhaps you might want to build a working knowledge of cryptography yourself. If you just want META not being able to see your NSFW chat with your romantic partner Signal might be more than enough. In fact, people way more relevant than me also suggest that Signal is good even for bounty hunter vulnerability reporting.
Having said that, what bugs me most is that people think the instant messaging format as suitable for everything: activism, jobs, crimes, broadcasting 1970's prog rock for extraterestrials , whatever lmao. Do you really want to use your phone for all that? Like, just carrying the phone around in the first place nullifies your other precautions, for all advanced threat models beyond privacy of non-critical social messaging.
Persistent/resourceful adversaries can eventually get to you, using a set of penetration and intelligence techniques, which means, if you are involved, the convenience of messaging your partners in crime from the phone in your pocket while waiting for a bus is a convenience you probably can't afford.
It's impossible to escape the surveillance of those three letter agencies. We only got a brief glimpse into the other side of the curtain back in 2013, and there is no idea how advanced their surveillance technologies are, so why bother for a normie?
It's also painstaking if not impossible to wipe all your metadata from the internet, which can later be mined to infer personal data and sold by data brokers. Not to mention that people have jobs and use their credit cards, no way even to hide the most important personal identifying information.
So using Signal, despite being centralized, is not too bad at all. Very few people can totally sacrifice convenience for privacy.
Exactly, this is a lost cause. If you participate in society your essential data are simply out there. For most people the task is to minimize their footprint. If we are talking about evading mass surveillance, then we should take for granted that the person will be to one or another degree marginalized, or lead a fringe lifestyle.