For me Matrix is fine, I can use IRC, Whatsapp and Discord with it. But Element is not my cup of tea, especially with Firefox as it doesn't play any videos other users are sharing. The same videos work fine with Cinny.

I am still mad that are no mobile clients that supports multiple accounts. So I am ending up installing for each account a different client.

Edit: added mobile.

I can use IRC

The fact that many Discord and IRC channels (servers?) block Matrix connections has drastically reduced its usefulness for me. When I was running my own Matrix server, I could have gotten around it by using a puppet, but Synapse is such a hog I had to shut it down, and most of the IRC rooms I want to use don't allow Matrix proxies.

The IRC (Biboumi) and Discord bridges (slidge.im) for XMPP work still fine and running your own server is super lightweight.

NeoChat on KDE allows me to choose which account to login to when I start it.

i want 90s era icq and 2000s era msn back

I agree with all this. The thing which caused me to uninstall was suddenly being pushed lots of abusive message with disturbing contents.

When I complained about it, Matrix told me that my public complaints were hurting the ecosystem and I should be quiet.

But they both closed source protocols locked down to specific corp

What would you propose, then?

Does it let you be logged in as both ?

I just want a self-hostable open-source alternative to the shitty closed-source IM systems I'm forced to use

I'm sticking with Matrix for now, hopefully some of the issues I've had will get ironed out

How about jabber/XMPP

Element Desktop has profiles. But sadly there are no profiles on the mobile app.

XMPP is still an option

When I complained about it, Matrix told me that my public complaints were hurting the ecosystem and I should be quiet.

Weird. I think they did some improvement to prevent those abusive messages but it took a while and it was embarrassing. Maybe it's hard to prevent them with a federated network but still, the abusive messages where basically a copy paste.

Fluffy chat allows multiple accounts

I wish xmpp was p2p. I can self-host but it could be way simpler if people didn't have to.

I wonder if Keet with every be open sourced. They still are missing a lot of features that I personally find important like trying notification, read receipt.