I bought an iPhone XS a month ago. On my old iPhone I made an iCloud Backup, then I deleted everything and gave my old iPhone to my mom (I don't use that iPhone anymore).
After checking in iCloud Photos on my Mac I confirmed absolutely every photo was there. On my new iPhone XS I chose the option "Restore from iCloud", all apps were restored, but unfortunately not all photos and videos.
I noticed this a few weeks later when I was looking for something. I was shocked that 30-40 files (videos & photos) were not downloaded from iCloud Backup. I tried repeatedly to restore them somehow, but I failed.
I know I didn't delete them, they just disappeared mysteriously after I backed up to iCloud.
These 30-40 photos are also now not available in iCloud Photos on my Mac. I do not know why. I am very sad because these were photos and videos from a long-awaited concert.
How can I recover these missing files?
Can I see the iCloud Photos upload history somehow?