Here’s how I understand it, and the kind folks at Medium can feel free to correct me if I’m wrong.

Personal experience means there’s a good reason you’re telling this story and that you’re uniquely capable of telling it for reasons specific to you. An example might help clarify:

Let’s say my article discusses Ancient Greek poetry. I’ve never lived in Ancient Greece (obviously!). I’ve never spoken Ancient Greek to an Ancient Greek. But I do understand the language(s) of Ancient Greece and offer my own translation of a poem alongside translations from the professionals to discuss them in context. I’ve studied it for years and have enough working knowledge of the language/culture to offer such a translation. That would fall under (unique) personal experience.

A heavily-research-based deep dive is similar.

I think by “write-around” they mean: a lot of writers try to churn out articles like they’re on an assembly line—they pick a topic, write a short personal story, then turn to Google and re-phrase whatever facts they find in their searches and call it an article. This isn’t really research, and the writer isn’t contributing much value to the story (and that’s being generous). Anyone can Google the same information or use ChatGPT to get a witty, clever summary.

That’s very different from the deep dive, or the Ancient Greek fanatic, both of which convey a genuine understanding of the subject.

The difference is the difference between stringing together 10 Google searches on a subject and communicating the depth of knowledge that comes with reading 10 books on it (or studying or teaching it for 10 years). You can’t Google or ChatGPT that experience.

I think Medium would love to see us write about the subjects we’re deeply passionate about and we spend our time on in our lives, and I think writers would do well to write about topics they love so much they could talk about it all night long with likeminded people and not get bored or tired.