This is called a First Person Epistolary, which is presented as a fictional first or second hand account of the events of the story. Such styles were popular in gothic horror works and can be found in Dracula, Frankenstein, Jekyll and Hyde, as well as works in other genres that include "Heart Of Darkness", "20,000 Leagues Under the Sea", and "Sherlock Holmes."
In a epistolary style, the narrator is telling a story to the reader that they have little to know agency in themselves. That is, while they may be along for the ride, they are merely recounting the actions of others in the story and retelling it in a form that reads more like a letter to the reader or a news paper article.
While in a traditional First Person, the narrator is part of the action of the story and almost always the protagonist of the story, in a epistolary style, the narrator is a witness, but not the protagonist of the story.
A modern work I can think of is some scenes in How I Met Your Mother which is framed as a father (future Ted) telling his kids the titular story, which is set in the present day (at the time of airing). During some episodes, in many episodes, Ted will have no agency in the B-Plot at all and logically Future Ted should not know about these events. When this happens, Future Ted will usually have a line of dialog that explains that he wasn't there and that the story was told to him after the fact. Typically this will occur immediate prior to an event that is likely exaggerated but faithfully depicted on screen as if it actually happened ("Now kids, I wasn't there, so I can't say this happened, but your Aunt/Uncle (character making the claim) swears this is how it happened:" cue depiction of an exaggerated action).
Other examples, in audio-visual mediums, will be depicted entirely or mostly from cameras in universe. Both The Office and Parks and Recs are filmed in such a way that give the illusion the footage was taken from recordings made by a documentary. Thus the characters will look knowingly at the camera, and have talking head segments.
In film, this will often dip into the Found Footage sub-genre, where the camera and the camera man are part of the action and the movement of the camera is in response to real world events. Cloverfield, Chronicle, and the Blair Witch Project are all examples of this genre. Chronicle in particular depicts a Superhero/Villain fight in downtown Seattle entirely from "in universe sources" by adding additional sources such as bystander's cellphone photoage, security cameras, and first responder dash cams. Interestingly, news media footage was only used by on tv sets in universe (Or was likely used raw before Kyron were added.) while Cloverfield and The Blair Witch Project were filmed with a single camera.
EDIT: I originally used the wrong term for this, it's actually "First Person Epistolary" and have updated accordingly.
Wikipedia has an article with a list of novels and there are some in the 21st century, with We Need to Talk about Kevin and World War Z: An Oral History of the Zombie War being the two big titles I picked out (again, haven't read either, but not sure how much the protagonist acts to affect the story.). If you'll pull back your definition of "Modern" Carrie (1974) is probably the best modern example as it tells the story through news reports as well as memoirs from survivors, arranged in roughly in universe chronological order. Thus the narrators change over the course of the novel, but none are protagonists. The most used memoir is that of Sue Snell, who was indirectly instrumental in the novel, but was a bystander by the time of the conclusion.