Sure looks a lot like Med Jets crash from earlier this year. Which was also a Learjet, albeit a 55.
#3 | POSTED BY SNOOFY

Both were also flying IFR ...

In freezing air, request to climb, then sounds like icing, lost lift 20,000ft/min ....

Lawn dart. No one will survive that.

Some photo evidence that the stabilizer came off. That's seldom a good thing.
#7 | Posted by REDIAL

It's possible it froze and broke off given forces to move.

They requested higher altitude. But for some reason flew right into a very small cell of questionable weather.

-47C

But looking at the video stills it appears in tact, though shrouds around engine was missing.

Also the copilot stated 60 degree banking. Which sort of indicates all 4 corners were together at least at the start of the "descent"

The max maneuvering speed for this plane was 205kt, and for sure it wasn't close to GW, so less than this.

It was travelling at ~400kts, which is ok in no turbulence conditions, but looking at the radar they went right through a cell at time of "DESCENT".

So yeah, the horizontal stabilizer and elevator might have failed.