This may be a massive leap on my part but I will toss it out.I guess it might involve resetting the whole “People & Pets” Album / Database though. I am NOT talking about Photos.app / Memories crashing specifically (this worked on my end), but only the detection of faces, which got completely wasted with macos 14 Sonoma (upgraded from Ventura) & OCLP 1.0.1. I cannot imagine that it has to do with Sonoma at all
There are starting to be some iCloud syncing issues reported relating to Sonoma file permission changes to iCloud based files.
On my OCLP Sonoma test system I have been seeing an error come up in Settings "Some iCloud Data isn't Syncing" with an explanation "Your end-to-end encrypted data isn iCloud can't be accessed on this device."
Apple Photos people identification is a piece of encrypted information propagated across your various devices.
If any form of Photos recognition isn't working on your Mac, if you also have an iDevice try identifying the person or pet on an iPhone or iPad using 17.x to see if this syncs.