For the life of me I can't see why people use this over Matrix. But if it was because you want an AppImage for the client, then here: https://appimage.github.io/element/
Signal is also nonprofit, fully opensource and minimizes metadata to a minimal amount (e.g. [0]), so it might not be as good as Matrix, but it's certainly not as bad as Whatsapp.
That's the first time I see this client mentioned. Maybe in a few years, the dust will have settled and there'll be a prominent Matrix client that's the obvious choice for most users. I don't think it'll reach widespread use before that.
Matrix is just not there yet. Hopefully soon, but not now.
Meanwhile, Matrix servers just ... log everything by default? https://github.com/matrix-org/synapse/issues/4565