For a pistol in a combative environment, I would go with a standard round in a reputable platform (HK, Glock, Sig, Etc). A long gun trumps a handgun for speed, accuracy, and power. Assuming you intend to shoulder the shockwave, and it works well being used like that, it would be a more capable platform.
Of course, the biggest question is what can you handle well? If you have trained a lot on a regular pistol, but not a long gun platform, the pistol might be a better choice.
My 10 year old daughter can shoot an ar15 well. It ain’t hard.
