Have you enabled "Show Related Content" in Photos?
Youmay want to check the Settings that open when you open the Photos.app, then tap your user icon for recommended Content. the upper right corner and scroll down to the settings .
Also check in the Settings.app the Settings > Apps > Photos > Apple Intelligence & Siri.
Photos has been removed to the "Apps" menu at the bottom the Settings.
Enable the checkmark for visual Search at the bottom of the Photos Settings.
Photos may need to scan your Photos Library again. So it may take a while until you are seeing the visual lookup again.