I think Smith or Ruger makes a .22WMR version of their 5.7 pistol. You could use that for a portion of practice, and it’d be a cool companion gun.

I must ask, how often does this match recur if you’re considering buying a gun specifically for it? No judgement; there are sillier reasons to buy a handgun or three. I’ve been acquiring the gun and parts for a USPSA Open Major G32 just for laughs, and it’s not like I’m going to shoot that division often.