Same problem here. Have had a case open for months with apple. Now my phone is out of storsge because photos have not backed up since December.

If it helps anyone my case number for this issue is 102213394298 this was the last update i received on 4/27/24: Case Number: 102213394298 I reached out and its currently still being investigated at this time. They recommended that you archive your photo and videos for an offline copy to reference. https://support.apple.com/en-us/HT204055#photos. I have attached link in case you would like to. I apologize for how long this has and is taken. But I do tank you for understanding and your patience so far