I think quite a substantial bit of AI-content is pretty blatantly not human generated. As you pointed out, it leans into third person. And, the phrasing is not how anyone talks, not even people for whom English is a second language.

Of course, Grammarly and similar editing software can push people into changing their style with corrections. Grammarly certainly seems to be bent on making every piece of writing sound like it's from the same mechanically correct voice.