Curious to know what's awful about slack specifically. For me, I don't like to get lost in a bazillion channels, pins are not global (`saved for later` is), there is no personal message queues etc.
Not so much a laundry listening more that it feels wrong as it is clearly an electron app and doesn’t feel like a native app and chooses to have its own conventions over embracing feeling like a native app.
I think that causes some of the issues you are mentioning.
Now I don’t personally see any communication app like slack that is any better than it. They all sort of suck but I feel like I had a better time with IRC apps back in the day than I do with modern communication apps.