How can I disable facial or object recognition in photos on apple devices?

You cannot disable the object recognition. Most of the features in Photos are relying on the object recognition - the searches, the Memories. The object recognition replaces the keywords and titles. Photos iOS does not have any support for smart albums or keywords or titles. If you want to find specific photos in your Photos Library, you need the recognized scenes and objects to be able to search for certain events, because you cannot add any titles or keywords on your own.

If you are concerned about the named faces, do not add any names to faces that Photos detects and do not link them to your contacts.

What would you go to? Android phones also do face matching, and, unlike Apple, that information is uploaded to Google Photos, where it is accessible to anyone you share photos with, and with Google as well to build their face database, which they share with businesses and law enforcement. With Apple Photos the face matches are only available to your iCloud account.

You can't turn it off.

Why do you think it's invading your privacy? The information is never sent anywhere. Apple get the information. People you share the photos with don't get the information.