Windows Security deletes threat protection history automatically, but it didn't delete protected folders access history, is there a way to delete it manually?
Yes, you can delete it manually. Go to Settings > Privacy > Activity History > Clear Activity History. However, remember this will clear all activity history, not just for protected folders.
Detection is only one stage. An antivirus can stop a threat before, during, or after execution. Check whether a test measures file detection or the system's final protection outcome.