Photos "copy link"

Perhaps you've reviewed &/or tried some ideas as

as presented in the above linked Related Article..

Get help with the Photos app on your Mac - Apple Support

Those are main 'troubleshooting methods' in Photos.

Among those, create a new Photos library may help.

"If you're experiencing other issues—like missing or blank photo

thumbnails, unexpected behavior, or if Photos won’t open—try to

see if it's an issue with your library by following these steps."

"Create a new Photos library and see if your issues persist:

1. Quit Photos.
2. Press and hold the Option key while you open Photos.
3. In the dialog that appears, click Create New.
4. Give your new library a name, then click OK. Note whether

Photos opens successfully with this new library.

"To return to your main Photos library, quit Photos. Then open it

again while holding the Option key, select your main library, and click

Choose Library."

Alternatively, you can open Photos in another user account on your Mac 

and note whether Photos opens successfully.

If Photos opens with the new library, or in a different user account,

it might mean that there's an issue with your library. Follow the steps

to use the Photos library repair tool on your main Photos library."