they were only 60 miles from the destination. That descent would represent a normal profile, and as you also pointed out it is important to keep the engine power up to keep the bleed air up for anti-icing. It is a tricky balance.
60 miles out is only 8~10 minutes out and 41000/8 is 5000 FPM!
So you start down.
35000/8 is a slightly more sedate 4400FPM < sarcasm intended>
"the last couple of datapoints are artifacts rather than actual altitude"

Those are not ballistic telemetry systems.
That pre-crash profile was far outside the predicted operating conditions that the static system was designed for.
ADS-B is reported by equipment on the aircraft. It was having a bad day by then.
Pilot error comes in all sorts of flavors.
Get there-itis will cause all sorts of poor decisions. You see what you want to see on the airborne radar so you see a way through where none exists.
I also want to point out that the 6000 feet difference from 35K and 41K is nothing in convective activity. It will move 6000' while you watch, in just a few moments not minutes.