But if you want to replace Slack, you need to focus on the developer community and third-party integrations right now. We're not paying for something that only gives us "just" chat with better-by-design UX and chat workflows. Teams is free and fits this purpose, at least in the eyes of an executive.
Slack's developer environment (outside of Grid features, the new "Premium Workflows" and "Next Generation Platform") is first-class.
At the very least start with some webhook integrations.
Also your Privacy Policy has no mention of Amazon Web Services, I think you might want to review your "DATA PROCESSORS / SERVICE PROVIDERS" section.
Also, are you planning on offering single-tenant options? Not a fan of our chat data sitting with a bunch of other organisations.