Go to filefindphotos. Delete as many unnecessary photos. Empty trash. Move the rest of the photos to iCloud Drive. Update to macOS Big Spur. Worked for me with to much disk space.
Daisydo
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
From
Twin Falls, ID, United States