I don’t think you know what centralization/decentralization means.
On matrix, you scan spin up a server/instance and communicate with any other matrix server/instance. On Fluxer, if you self-host, and your friend also self-hosts, your instance/server cannot communicate with your friend’s instance/server. You would have to create an account on your friend’s instance/server and vice-versa. You would also, probably, have to be running two clients in order to chat in both servers/instances.
Fluxer isn’t entirely centralized. It has self hosting support.
It’s quasi centralized pretty much the same as matrix.
You can just opt to not use the central server for hosting services.
What?
I don’t think you know what centralization/decentralization means.
On matrix, you scan spin up a server/instance and communicate with any other matrix server/instance. On Fluxer, if you self-host, and your friend also self-hosts, your instance/server cannot communicate with your friend’s instance/server. You would have to create an account on your friend’s instance/server and vice-versa. You would also, probably, have to be running two clients in order to chat in both servers/instances.