Photos on icloud
I had an iphone 5s before and I was using Icloud to save my photos. Now I have an iphone 8 & I want to see all photos but I can see only 270 photos in new iPhone
If you go to iCloud.com/Photos using a computer browser, how many do you see? If more than 270, try Settings/Your Name/iCloud and slide off syncing. Wait a few minutes and then slide syncing on.
Last resort - have you tried signing out of iCloud and then sign back in?