Again, no. The aircraft is not, by any stretch of the imagination, "unstable", let alone "inherently unstable" (in what way is that different from "unstable"). It just does not provide enough adverse stick force to satisfy a very specific certification requirement.
When it gets to a certain angle of attack, the engines, given the size and the forward/upward mounting, provide an unexpected amount of lift. This is the reason MCAS was developed, to push the nose down.
Poor design of the engine/wing configuration 'fixed' (so far not successfully) with software... the other fix, to turn off the AP, really? That to me is unstable design.
4 units per second would be a feat to behold.
Exactly, and likely at full speed!