In this article, we'll explain how to delete photos from iCloud without deleting them from your iPhone.
How to Delete Photos from iCloud But Keep Them on Your iPhone?
Syncing must be turned off to ensure that photos deleted from iCloud aren't also deleted from your iPhone. To check if iCloud Photo Syncing is enabled on your iPhone, follow these steps:
From your iPhone's home screen, open Settings and tap your Apple ID.
Select iCloud > Photos.