https://github.com/processone/fluux-messenger is an XMPP client by the ejabberd people that seems aimed at being a Discord alternative. I think it is intended to support voice and screen sharing eventually, though it looks like they want to focus on getting text chat worked out for the time being.
I’ve had an issue with controllers before because Steam’s udev rules straight up give the wrong permissions to the device files they create. Check Steam logs, there’s one specifically for controllers if I remember correctly (or maybe it was a generic “console” log) and it should be very clear if this is the issue because there will be a permission error recorded.
The title is really missing a keyword from the actual quote… (emphasis mine)