This is my point as well. I can see the Slack model of basically completely independent workspaces works well for something that I am doing full-time but for open source work it is just too much effort to follow. Discord is better but I still find that switching between different servers is a lot of clicking and for non-focused servers you only see server-level read/unread.
I really like the Matrix (and WhatsApp, FB Messenger, Telegram...) model where every chat is just a different room that I can have in one recency list. Spaces of top of "just rooms" does a nice job to help discovery and filtering.
At least for how I work Matrix "Spaces" is actually the best UX for my personal life as opposed to "Servers" or "Workspaces". Element could definitely improve on other fronts but the way it "merges" my different communities on the client is excellent.