Which system version did you have installed before the upgrade? And how did you upgrade? Did you make a clean install and erase the Mac, or did you just install the new system version on top of the old system version?
Photos is storing your photos in a Photos Library. To recover your photos, you have to point Photos to the correct Photos Library.
By default, Photos will create your Photos Library in the Pictures folder. Did you leave the Photos Library there or did you move it to an external drive, to save storage on your Mac? If you moved the library to an external drive, check, if your external drive is compatible with photos. While older system versions did not always complain, if you moved your Photos Library to an unsuitable disk, macOS 13 Ventura may not be able to work at all, if you are using an incompatible external drive for Photos. Any external drive needs to be prepared exactly as described here: Move your Photos library to save space on your Mac - Apple Support
If you Photos Library is in a supported location, quit Photos, if it is running, then hold down the options key ⌥ while launching Photos and select your Photos Library from the dialog that opens.
Or did you enable the Shared iCloud Library in the Photos > Settings > iCloud? If you did, and let Photos automatically move the photos to the Shared library, you will no longer see them on devices with an older system version. And you have to set the library switch in the toolbar to "Both Libraries" to see all photos.