It's good that you have tried repairing the library-- that's always a first step. (Well, after restarting the computer, of course.)
I'm worried that you might have your library stored on an external drive that is not formatted for Mac. If a Photos Library is stored on an external drive it must be formatted in either APFS format or in Mac OS Extended (Journaled) format. If you're using exFAT or some other format, you can't get full functionality, and it can even damage the connections needed for the Photos database. The format of the external drive must be verified before trying anything else.
Another question I have is, how are you importing these pictures? Do you use a cable or iCloud or AirDrop? Are you using Photos>Import? Have you tried the app Image Capture from your Applications folder?
If nothing else works, then try starting in Safe Mode (this is different for different computers)
Start up your Mac in safe mode - Apple Support
Safe Mode bypasses certain potentially disruptive processes, including automatic login items.
Also, how are your preferences set, especially:
In Photos>Preferences>General,
Is "Use as System Photo Library" grayed out (indicating it is) or solid (indicating this isn't your system library)?
Is "Copy Item to the Photos Library" checked? (This is the default, indicating a "Managed Library")
In Photos>Preferences>iCloud
Is "iCloud Photos" checked?
If it is, is "Optimize Mac Storage" check?
Let us know what happens.
