Pitch up tendencies under power to my understanding don’t make it an unstable airframe. If you stall, cut power, let go of the controls and the plane responds w

Pitch up tendencies under power to my understanding don’t make it an unstable airframe. If you stall, cut power, let go of the controls and the plane responds with a recoverable dive, it’s aerodynamically stable. Some airplanes can’t be (reliably) recovered from stall, that’s another issue altogether.