Tangential.

Is there a name for this style of writing? I come across it regularly.

I'd describe it as forcefully modest, "I'm just a simple guy" kind of thing. With a dash of "still a child on the inside". I always picture it as if the guy from the King of Queens meme wrote it.

"I guess I'm just really into books, heh" - Bezos (obviously non-real, hypothetical quote, meant to illustrate the concept)

This style is also very prevalent in Twitter bios.

Since it's a "literary" style that is quite common, I'm sure it has been characterized and named.

GPT says it's "aw-shucks", but I think that's a different thing.