Yes, but Signal and Matrix-something aren't good "messaging" apps. Just a bunch of poorly written desktop and mobile clients tied to questionable backends and metadata disasters.

Maybe not Signal: https://dessalines.github.io/essays/why_not_signal.html

CIA Funding CIA → RFA → OTF → Signal. While this article by Yasha Levine gets into the details, it is no secret that the original funder of Open Whisper Systems (the previous name for signal’s development team), was the Open Technology Fund: itself publicly listed as a subsidiary of Radio Free Asia, a US state-run organization whose main goal (along with the other “Radio Free” incarnations such as Radio Free Europe, or Free Cuba Radio) is regime change for those Asian governments who don’t align with the US’s foreign policy interests.

You can’t recommend Signal over anything when it comes to features and service quality it just can't handle large group chats (hundreds of people) and the cross device sync fails often with a “signal can’t display this message”. Signal’s desktop and mobile clients are simply a pile of react and javascript garbage that can never be as fast as the native applications from other apps.

Maybe not Matrix: metadata disaster

Matrix’s E2EE does not, however, encrypt everything. The following information is not encrypted: Message senders, Session/device IDs, Message timestamps, Room members (join/leave/invite events), Message edit events, Message reactions, Read receipts, Nicknames, Profile pictures

Matrix is developed by a for profit entity, a group of venture capitalists and having a spec doesn’t mean everything. The way Matrix is designed is to force into jumping through hoops and kind of draw all attention to Matrix itself instead of the end result.

Decentralized communication protocol Matrix shifts to less-permissive AGPL open source license Element, the company and core developer behind the decentralized communication protocol known as Matrix, has announced a notable license change that will make the open source project just that little bit less appealing for companies looking to build on top of it.

https://techcrunch.com/2023/11/06/decentralized-communication-protocol-matrix-shifts-to-less-permissive-agpl-open-source-license/

Stop recommending questionable open-source like Matrix. XMPP is the true and the OG federated and truly open solution that is very extensible. XMPP is tested, reliable, secure and above all a truly open standard and decentralized it just lacks some investment in better mobile clients.

What people fail to see is that XMPP is the only solution that treats messaging and video like email: just provide an address and the servers and clients will cooperate with each other in order to maintain a conversation and it can be configured to be secure and private. Everything else is just an attempt at yet another vendor lock-in. Here a quick overview of the architecture.