Trying to keep things incredibly simple, without recourse to any equations, the 'traditional' 'high speed stall' is when a wing is taken to or past its stalling angle at a speed above the straight and level stalling speed. Normally this will occur when manouevring.
Such a 'stall' is easily recovered by reducing the angle of the wing to below that stalling angle, normally by relaxing the tailplane/elevator input that has caused the angle change.
So, letīs go back to the case of high speed stall considered in this thread!
So, an aircraft flying at high TAS and Mach number but at low IAS (because at a high altitude close to its ceiling) and high AoA close to stall already (perhaps heavily loaded) encounters, at previously unchanged pitch attitude and control positions, a sudden updraught. Which might be caused by wake turbulence, or by CAT around a jetstream, or mountain waves, or, say, occur around a thundercloud that the plane is trying to fly above.
Suppose that the updraught increases the AoA right through the stalling AoA so that Clmax is passed and lift actually falls below 1g. What next?
And you could have bank or spin because one wing met an updraught while the other found a downdraught.
As for business jets, note that they usually have rear engines. While some of them (Jetstar, Falcon, a few others) have +-tails, many have T-tails. A known deep stall hazard, and stick pushers would not have time to react to a sudden updraught.
For example, a Russian Tu-154, struggling at a heavy load and tail heavy CoG to fly over a thundercloud near or above its ceiling entered a flat spin that brought it right into the thundercloud it had been trying to avoid - and right through the cloud into Ukrainian soil. Could a wake turbulence likewise blast a plane into a flat spin?