The "Secure Folder" on the Samsung device cannot be simply deleted, but must be deactivated or uninstalled via the settings. This will delete all content such as apps, photos, contacts, documents or files. After uninstalling, the "Secure Folder" can be recreated.

Android 10 (One UI 2.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Biometrics and security
Step 3:  Tap on  Secure Folder
Step 4:  Tap on  More settings
Step 5:  Tap on  Uninstall
Step 6:  Confirm with  Uninstall
  1. Open the Settings
  2. Tap on Biometrics and security
  3. Tap on Secure Folder
  4. Tap on More settings
  5. Tap on Uninstall
  6. Confirm with Uninstall

Samsung Instructions