On my iPhone 14 Pro this scanning process never progresses. It has been at this status for at least the last week or so. Anyone else?
And it's been locked and connected to power the whole time? That's a large number of photos, and it needs long periods of being locked and connected to power. Are you allowing that to happen perhaps overnight?
I don't know how to account for the totals (79,158 vs 76,109), but it's only trying to scan 4,395 remaining photos.
Have you tried quitting the Photos app and rebooting your phone to see if that helps the remaining scans move forward?