I've got a math minor, which was really by accident and rightfully impresses no one...and I wouldn't trust myself to calculate a tip after 9pm, but, guessing - guessing that the max groundspeed and max reported decent rate happened at roughly the same time, I came up with about 30 degrees down and something like 150 knots velocity. I made that guess because I figured as long as the plane wasn't dropping out of the sky stall/spin style, and the wings were attached, the faster it's going down the faster it's going horizontal, too. (Or in other words I assumed it was <45 down, so the point of max horizontal velocity would be the same as max vertical.) Many assumptions with that, though, including that there's any validity in the posted numbers from ADSB, and that I wrote them down correctly and did the math right.
I'm going to guess again, and that's that if the pilot didn't understand how serious being over Vne can be, OR that they were going that fast, she might not have realized how big a problem it was until too late.
Assuming there's nothing unexpected that NTSB finds, my curiosity is what the throttle was set at, if they can tell. That should be part of anyone's training for unusual attitudes, but sometimes people don't do what they were trained to do.