None of your user's data will be deleted. Whether you deactivate a user in Nikabot or you eliminate them from your Slack workspace or Teams, any hours they logged and projects they created will still be accessible.
In case you delete a user from Slack or MS Teams, if you don't deactivate them for time tracking in Nikabot, you will still be able to add and edit their records through the Report Center.
After a user is deactivated for time tracking, you'll be able to edit logs from before they were deactivated, and their missing hours will only count towards the Team Overview dashboards metrics on the timeframe during which they were active.