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.
Keep recovery media reachable. Prepare recovery media before you need it and store it safely. A recovery drive and a backup of your personal files serve different purposes.