Recovering photos

From my previous reply: If iCloud Photos is turned on in a device then the same photos are not also included in iCloud Backup of that device.

Also see the following from What does iCloud back up? - Apple Support

Your iPhone, iPad, and iPod touch backups only include information and settings stored on your device. They do not include information already stored in iCloud such as Contacts, Calendars, Bookmarks, Notes, Voice Memos3, Messages in iCloud, iCloud Photos, and shared photos.

They can be recovered from Recently Deleted. See: Get help with missing photos – Apple Support

If iCloud Photos is turned on in a device then the same photos are not also included in iCloud Backup of that device.

If iCloud Photos is turned on in a device and if the photos are deleted from the device and then they are also deleted from Recently Deleted, then there isn't a way to recover them from iCloud.