One of the few features of the Galerie app is album deletion: if an album is deleted on Oppo smartphone, the album itself is removed, and the contents such as photos or videos are moved to the trash for 30 days.

Android 10 | ColorOS 7.0
Step 1:  Open the  Photos -App
Step 2:  Tap on  Albums
Step 3:  Open the  Menu
Step 4:  Tap on  Edit
Step 5:  Select all  Albums  you want
Step 6:  Tap on  Delete
Step 7:  Confirm with  Delete Album
  1. Open the Photos-App
  2. Tap on Albums
  3. Open the Menu
  4. Tap on Edit
  5. Select all Albums you want
  6. Tap on Delete
  7. Confirm with Delete Album

Oppo Instructions