The groups or labels created in the Contacts app on the OnePlus smartphone can be deleted at any time without having to manually remove each individual group member.

If a group is deleted on the OnePlus device, all members located there will be removed, but will remain in the contacts list.

Android 10 | OxygenOS 10.0
Delete group -  Open the  Contacts app
Delete group -  Open the  menu
Delete group -  Choose a  label/group
Delete group -  Open the  menu
Delete group -  Tap on  Delete label
Delete group -  Confirm with  OK
  1. Open the Contacts app
  2. Open the menu
  3. Choose a label/group
  4. Open the menu
  5. Tap on Delete label
  6. Confirm with OK

OnePlus Instructions