I'm grateful to Slack for their changes in the free plan, it forced our hands. We realized it's obvious we can't trust any of these external SaaS services, in the long run they will ALWAYS change the terms and somehow fuck the customers, paying or not. And then you will lose all the invaluable information and data that belongs to you. This has happened with other services we've used in the past too. So we decided to…
You're not a customer, you don't pay for the product. If you want to be treated like a customer, then pay for the product. This entitlement mindset is extraordinary. Slack was literally paying for you to use their product. Regardless, it sounds like you're happy with your move.
I had two slack workspaces for completely different projects/companies. I set the other one up early this year and we were slowly migrating to it after another SaaS went bust.
I was going to start paying for that workspace too, because I needed the extra features. Luckily they showed their true colors first and I got a chance to migrate away early. I don't want to deal with their whims long-term.