@lightweight Just to help you make sense of this: no, NextCloud Talk and Matrix are not "at least as good" as Salesforce Slack, and Zulip UI is more or less frozen from the time it was created. They are, in fact, quite clunky. I haven't used the others.

Also, corporations don't want to self-host their chats, and some of these product don't really have a solid managed offering.

So, in summary, the first step is to avoid comparing things that cannot really be compared.