Look, slack is 1000% better than Teams will ever be. But, Slack is also enshittifying themselves, eg. with their 3-month event horizon.
Anything Slack can do, Mattermost does – and Mattermost is free, open source, and self-hostable.
This is my hill.
HyperCard! There’s a name I haven’t heard in a while. It was marvellous, for its time.
I’m appalled to see it compared to some shitty MS product (that I have no knowledge of), and I’ll just add that I have never encountered our hard of this bonkers “previous page is still active” issue in HyperCard - but I readily believe it’s there in 365.