When a user sets an inactivityTTL in the template schedule page and there are already inactive workspaces that will be immediately scheduled to be deleted, we should inform the user and allow them to take action via a modal, e.g.

30 workspaces already match this filter. These workspaces will be scheduled for deletion in 14 days.
[Confirm] | [Cancel]

"Confirm" would go ahead and set the inactivityTTL, "Cancel" would cancel the action altogether. It would fall upon the user to do something about those 30 workspaces prior to going back and attempting to reset the inactivityTTL.