How to delete unused cloud backup with one plus 9RT?

When cloud backup is turned on, SMS, call history, application list and layout, and system settings on the device will be automatically backed up to the cloud, and the backup frequency is 1 day, 1 time. You can turn off cloud backup or delete old backup to reduce the space occupied by backup data in cloud storage.

Go to settings > cloud service > whole machine backup.

Select the backup you want to delete, and then click Delete.

Turn off the "whole machine backup" switch, and the system will stop the automatic backup, but the original backup will not be deleted.