Black mirror is a lot like a modern Twilight Zone, which early Star Trek was significantly influenced by, and now a fan who directed an episode inspired by Trek gets to do actual Trek?
Well, as long as it's nothing like that episode, it should be fine.
I remember an episode of CSI years ago where they were investigating the murder of someone who was rebooting a very Star Trek show into something super dark and gritty, with none of the hope and positivity the original show had. That seems to be the trend of a lot of Star Trek properties the last few years, and it makes me think the writer of that episode was quite prescient.
The impact to the timeline form the Narada affected the timeline before that point as well because it affected subsequent time travel (allllll the times SNW, TOS, TNG, VOY, DS9, etc. went into the past would have occurred differently)
I find "USS Callister" especially funny because early on in Disco's run, people would point to it as what new Trek should be, but the episode is all about how someone obsessed with an old sci-fi television show is a loser and a creep, and then it ends with the protagonists getting a Kelvin universe-esque upgrade, lens flares and all.
That's why Willful Child is probably the better Star Trek fanfic, where it's like "what if we really emphasized how much of a misogynistic asshole Kirk could have been?" Or "what if we merged Kirk with Zapp Brannigan?"