The Walt Disney Company is reportedly ditching Slack after a July data breach exposed over 1TB of confidential messages and files posted to the company’s internal communication channels.
NIH isn’t healthy either to be honest. Plus when some service fucks up, you may have legal recourse. If it’s your own employees, you can fire them but won’t get much money out of them.
Purchase a tool and self host. You can’t un-leak data no matter how much money you get.
You are in charge of internal policies and can enforce them.