Do you have any photos in your Photos Library, where you have only one photo of the person?
For the albums of these people you may see the message about finishing the scan for a long time, because Photos is waiting for more detected faces of these people - it is needing at least two automatically detected faces to be able to learn to recognize the person automatically.
The mac and the iPhone are using different system versions and the face detection algorithm may differ on the iPhone and the mac, so the results may be different.
Have you already used the "confirm additional faces " dialog on your Mac for each people album? Some detected faces will not be shown, until you have confirmed all detected faces.
If there are still photos and videos, where Photos should have found faces, but you are not seeing any faces marked, you may want to check, if these items can be processed by Phots at all. Sometimes Photos cannot access the original of the photo or the video, or it may be in an older legacy format, that is no longer supported on macOS Ventura. Then you need to remove the older version and convert it with a new version in a supported format. Legacy items can cause the background processes to get stuck on this items. Sometime such problematic items will appear in an album "unable to upload". I would start by checking the videos, if they can be edited.