Photos: cannot import item: the selected photo library must be repaired before it can be imported……

Where is the Photos Library stored, that you want to import?

A common reason for not be being able to import a library is keeping a library on an external volume with an incompatible file system format. Before try to repair the library, make sure it is on an compatible volume as described here: Move your Photos library to save space on your Mac - Apple Support

If you try to repair a library on an incompatible volume, you may make the damage worse.

Any external volume you are using with Photos needs to be prepared like this:

• The file system format needs to be MacOS Extended(Journaled) of APFS
• The external volume must not have been used for Time Machine backups or have any backup software installed.
• It must not be mounted on the local network but use a wired connection.
• The library must not be in a synced folder like a Dropbox or on Google Drive or similar
• As a test: if you cannot set the Ignore Ownership on this Volume Flag, the external volume is not suitable.

Even if you could use the library with earlier versions of Photos, there may have problems all along. Photos 8 on Ventura is checking the location of a library more thoroughly than earlier version to prevent damage.

To repair a Photos Library see: Repair your library in Photos on Mac – Apple Support (UK)