Apple would be able (and perhaps required?) to provide the decrypted data. TLS is not end-to-end encryption; it’s just server-to-client. It’s useful to prevent MITM wiretapping but it is NOT useful to prevent server-side spying.

The article quotes Apple as saying they can update their transparency report now that this is public. Doesn’t look like they have data for 2023 yet at https://www.apple.com/legal/transparency/

I’d think Apple could make push notification content end-to-end encrypted if they so desired, but I don’t know how they could avoid having access to the vendor and user at minimum for the sake of validation and delivery.

The article states that Apple recommends not putting any sensitive data in the payloads as well as encrypting the payloads

This sounds a lot like a scenario where Apple informs that a mechanism used for standard mobile communication is being survived by governments not necessarily a scenario where something Apple or google are doing is inherently surveillance.

Here it seems like the surveillance is occurring at the 3rd parties who send the push notifications.