All in all, it looks like this was a mistake by Russian AD around Grozny. I've not seen
detailed 3D tracking info. for the entire flight, but some reports claim the plane attempted to land @ Grozny 3 times before it was hit, and was denied due to fog. There may have been an active threat to Russian ground assets from Ukrainian drones, with the Russians GPS jamming to counter. The airport @ Grozny borders a heavily populated area just to the south, including Grozny itself, so, diverting to a different airport more remotely situated likely made sense if the pilots thought they could get there: Well they may have, esp. if one of the hydraulic systems was leaking slowly enough that initially they still had some control.
The one thing that doesn't entirely make sense to me is why the Russian AD would not have known from Grozny ATC that a civilian airliner had been in a holding pattern for a while (or would be departing it.) A deadly snafu...? :-(