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.
Kind of limited due to there not being an iOS version, but Briar is pretty decent. It was made to be usable in repressive areas by press and other groups, as well as in areas where bad weather has taken out cell and regular wifi. Can be used with phone data, but also offline via ad-hoc wifi and bluetooth. But stuff like Signal and SimpleX are more overall useful to more people (and I think SimpleX also supports offline local immediate area of each other like wifi and bluetooth but I don't remember atm).