How to remove inaccessible backup storage from iCloud?

Managing your iCloud storage is generally quite simple and straightforward on an iPhone.

If iCloud Storage shows that 192.5 GB is being used by Backups, but when you open iCloud Backup you see “0 devices” and “0 bytes,” then there is a discrepancy that needs to be investigated. This could indicate that you are signed in with a different Apple Account than the one associated with that backup, or that you are looking at a different iCloud storage location or screen from the one where the backup is actually being reported.

The exact screen and the device selected are important here. From your post, it isn't clear at which stage you are seeing the 192.5 GB figure, which Apple Account is signed in, or which device—if any—is being selected under iCloud Backup.

On the iPhone, you can normally check the backup details by following this path:

Settings → [Your Name] → iCloud → iCloud Backup → Backups → Select your device

Once you select the relevant device, scroll down. You should see options relating to the backup, including the option to turn off iCloud Backup and, where applicable, delete the backup.

Before deleting anything, however, make sure you have identified the correct device and Apple Account. Deleting an iCloud backup permanently removes that backup from iCloud, so it should not be done until you are certain that it is no longer required.

The screenshot below illustrates the step-by-step process for locating the backup, viewing what is consuming the storage, identifying the device associated with it, and deleting the backup when appropriate.

If you are genuinely seeing 192.5 GB under Backups while the iCloud Backup section simultaneously reports 0 devices and 0 bytes, a screenshot of both screens would be useful. That would make it possible to determine exactly where the 192.5 GB is being reported and whether you are checking the same Apple Account and iCloud storage category.