Looks completely inaccurate, based on the trailer.

Short Term Conflict Alert (STCA) was not online at Skyguide that night, because the primary radar was offline for maintenance, and STCA was not available on the backup system. However the trailer represents an STCA warning seconds before the accident (it would have warned much sooner than that, had it been operational).

Peter Nielsen (no doubt not his name in the movie) was not tossing off, drinking coffee as if on a break, during the events. He was distracted by another unscheduled flight, and unable to resolve the issues with it because the phone system was being worked on and the backup phone system had a technical problem and was disabled. He was also working alone, due to Skyguide's policy or letting one of the two scheduled controllers take an "extended break" during low traffic hours.

Pilots do NOT just suddenly decide to descend to 10,000 feet because "hey, we haven't heard from you for a minute". The reason both planes were at the same altitude and got close was because the controller was distracted and forgot to separate them. An altitude of 10K would be inappropriate anyway, as neither of them were anywhere close to making an approach for landing. But, hey, since they are changing the airlines, changing the flight numbers and changing the location, why not?

This didn't happen in Ohio (The airport is named "Mid-Ohio International, but probably meant to depict Columbus International or Hopkins International). It happened over Uberlingen, Germany, on the southern border.

Vitaly Kaloyev was accurately depicted as an architect, but he lost his wife and a son and a daughter, not just wife and daughter. And his daughter was not pregnant, she was much too young. This was added for dramatics.

There is no way in HELL that VK was present during the search for, and removal of bodies phase of the investigation. Dramatics again.

The amount of persecution PN received during the investigation seems to have been exaggerated a bit. Also for dramatics.

Who knows for sure yet, but the trailer seems to indicate VK and PN both had guns, and had them in preparation for the inevitable showdown between them. Is a shoot-out likely to be depicted? In reality VK showed PN a picture of his kids in coffins and tried to get an apology. Upon realizing an apology was not forthcoming, he stabbed PN. This all occured in PN's backyard, not at his front door.

Yeah, yeah. I know. "It's a movie". I know. It's not even a movie, it's a movie trailer. Incomplete and highly edited.

But, assuming there are many more instances of "dramatic licence" to come here, it's looking to be a catastrophe at least as bad as the accident which "inspired" it.

Here is a link to an episode of Mayday, which is much more accurate than anything we will get in this over-dramatic waste of time.
https://www.youtube.com/watch?v=vZixPCeG4ss