Looks like a real photo with iOS’s image enhancements that automatically get applied to every photo.

No, looks like a still slightly grainy photo taken by one of the first phone cams 20 years back under extreme low light conditions.
Excessive lowpass filtering to get rid of the noise + clearly visible shake motion blurring (look at the letters) because of long exposure.

No recent phone camera performs that bad any more, let alone an Iphone cam...

But emulating poor performance cameras has been a tool of choice to mask fake image artifacts for a long time now.

Sabrina Carpenter is known for being a relatable goofball from time to time on social media.

That's the first real argument l heard supporting that this may not be fake!
A google search with some suitable search terms actually found a few unpolished non-publicity pics for me, but still none of these were comparable in any way to OP's one, though.