Give it a couple years, you'll learn to hate it. I have dozens of channels and countless group chats with 1-5 people. I was added to those channels when the channel members needed my two cents about something, but now I'm still in these channels, months later. Do I really want to be the guy purging all his Slack channels?

Just wait until you're trying to look up a really, really important message, but you can't figure out what word (or synonym thereof) to search for that will give you the results you need. Better hope you didn't leave that channel in an effort to clean up your channels.

It sounds like your organization already has a solution, which is a combination of GH issues and Jira. Slack is fine as a supplement to more structured methods of communication, but as the main communication method, it's a disaster.

Maybe Slack is better than the "unnamed but awful FAANG tool," but by your own admission, the bar is on the floor. We can do better.