I'd welcome any assistance in resolving an issue with my iPhone. The storage has been consumed by Photos as something has gone haywire between Photos, iCloud,and iOS. Here is a full post: http://ecrosstexas.com/blog/2018/your-iphone-storage-is-full
Out of curiosity, have you enabled 'optimize photo storage'? And how many photos/videos do you have?
I used to have lots of trouble with iCloud Photo Library, but it's largely been worked out now. What I found during a year or two of off and on trouble is that no one, even Apple, really know how it works and you wake up one day and it's magically fixed.