UR22C buffer on iPad pro M1

I’ve installed and run dspMixFx, but it doesn’t seem to see the interface properly. My IK B-3X Organ software does, which is great, it’s all I really want at this point, however: the buffer setting only offers 1024, which is not useable. I have the two units connected using the USB-C cable that came with the Ipad. Anyone know what I might try?