Crash: China Eastern B738 near Guangzhou on Mar 21st 2022 (opens in new tab)

I'm not sure if briefly levelling off for about 30 seconds is proof that the plane was "operable and could aviate". It feels more like the pilots briefly got some control back, before the situation worsened again.

Of course really trying to speculate at this early stage on limited data is pointless. We really need to wait for some hard information to come out of the crash investigation.

I wonder if it's possible that the increased speed from their downward trajectory generated enough lift to pull them out of their downward trajectory.

This "recovery" would be short, as their air speed slowed, lift decreased, and they then resumed their downward trajectory.

This is because flightradar24 measures ground speed. A rock dropped from a building has a ground speed of zero. The apparent recovery was due to the fact that the aerodynamics of a 737 in a nosedive force it to pitch up somewhat. But the pilot probably pushed it back down.

Possibly explosive decompression then they go way too fast on the emergency descent so pulling out of the dive caused structural failure leading to the crash.

AD 2019-22-10 included NG yes

http://www.b737.org.uk/picklefork.htm

No. It shows a complete loss of control.

There was an air crash episode on a crash from the 80s but other than that I can’t think of another complete nose dive crash.

Generally planes don't just fall out of the sky; accidents nearly always happen shortly after takeoff or when landing.