I have a lot of videos and photos missing from the app and from iCloud, even after being connected to WiFi (devise I’m searching on connected to a wall plug), updated and with full power (battery and internet connection. There are a few videos that do not load at all that once did. (See screenshot below.)
You need to repair photo library from Mac Repair your library in Photos on Mac - Apple Support if iPhone is synced with Mac ( signed in with same Apple ID and password on the same network , the error shown with exclamation mark in photos app from iPhone will also go away If you're missing photos or videos in the Photos app - Apple Support
Sign in with the same Apple ID
For your photos and videos to stay up to date on all of your devices, make sure you sign in to iCloud with the same Apple ID on every device.
You can check which Apple ID your device is using in Settings. You'll see your name and email address. Your email address is your Apple ID.
See If your iCloud Photos aren’t syncing to your device – Apple Support
You need to repair photo library from Mac Repair your library in Photos on Mac - Apple Support if iPhone is synced with Mac ( signed in with same Apple ID and password on the same network , the error shown with exclamation mark in photos app from iPhone will also go away If you're missing photos or videos in the Photos app - Apple Support
Sign in with the same Apple ID
For your photos and videos to stay up to date on all of your devices, make sure you sign in to iCloud with the same Apple ID on every device.
You can check which Apple ID your device is using in Settings. You'll see your name and email address. Your email address is your Apple ID.
See If your iCloud Photos aren’t syncing to your device – Apple Support
iCloud Is Disappearing Photos & Videos & File Corrupting Others
