Some users have noticed settings that let Meta analyze and retain phone photos

IMO Apple should provide the user with audit logs of which photos/videos were accessed by each app. It might be a long list but it alleviates doubt and would put huge pressure on reputable developers to ensure they don’t get caught doing things the user wouldn’t have expected (even if the user technically allowed it).

I don’t understand why apps need access to my photos at all. (with some very specific exceptions,) apps should only access a photo, which I first select using the system photo picker. There’s no need for apps to access the entire camera roll just so I can select one photo to use with that app.

I know that that’s partially implemented with the limited photo access now, but it’s confusing from a UI perspective and I don’t understand why this isn’t the default.

The only apps that need full access to my camera roll, are apps like Google Photos, Nextcloud or Immich. Everyone else can suck a lemon.

The copy/paste feature is underused on iOS. These days if an app needs access to a photo, I try to determine whether the app uses the system photo picker (which doesn't need the app to have photos permission). If it doesn't I simply use the Photos app to copy a photo and then paste afterwards. A benefit is that you can strip location right from the Photos app. With third party apps like Metapho which can be invoked from the share sheet, you can even strip all metadata before copying.

Some apps like WeChat somehow insist on building on their photo picker and they get the copy/paste treatment.

Apple should really had a "strip metadata" option directly in the photos picker widget. It would work well with their privacy marketing.

It does, and location and captions are stripped by default using the system picker. It's the switches icon in the bottom left.

Doesn't strip all metadata, such as make/model, ISO, aperture etc.