If you cannot see the Flow closure feedback response report, it could be because of two reasons:
The feature is toggled off: The Flow Closure Feedback Response feature is not active by default. You must enable the toggle within the Style or Customize section for Flows for it to start capturing data.
No users have closed a Flow yet: The dashboard remains blank until your end-users actually reach the end of a Flow, trigger the closure state, and then submit their feedback.
For more information on how to enable the Flow Closure feedback on Flows, see Flow Closure Feedback.
Note:
Ensure you publish the Flow for the changes to reflect. Any changes made from the Style section reflects on all Flows.