Have you done a dive test to adjust the center of gravity? That may lessen stalls and make a happier plane to fly.
From a crusing speed and altitude, throttle back to idle and nose down to 45 degrees, then center your stick. If it dives steeper, move the CG forward. If it pulls up, move the CG back. Works for model airplanes, even though it sounds counter-intuitive.
Can you make larger tail and canard surfaces, which are invisible outside the current configuration? All supersonic a/c need big tails to poke out of the shockwave, that's one reason the Bell X-1 was nearly unflyable near and above mach speed. Also there's not a lot of rudder area under the plane to keep it straight at high alpha.
Really, you don't want to bring a hard-to-fly a/c into combat. What with people shooting at you, trying to miss the ground and complete the mission you don't have the attention to spare for a misbehaving piece of junk. Any plane that behaved as badly as the '19 reportedly has (in Mac+) would have been scrapped long before Dyson showed up. Convenient plot element I say, the unflyable superplane meets the lovable rogue pilot!