Max Number of Cores for Simulator in Xcode Bot Run

Is there any limit on the number of cores a Simulator (iPad Pro 9.7" 13.6) will use when running unit tests as part of an Xcode Bot Integration run? I'm on a 2018 Mac mini w/6 physical cores and Activity Monitor shows all the physical cores in use (interesting to note all the hyper threaded cores remain all but idle).

If we wanted to get faster integration times, would moving up to Mac Pro with more cores do the trick? Or has a cruel fate come upon us and 6 cores is the max this Simulator can use?

I also have an ancillary question; is the
Code Block
-maximum-parallel-testing-workers

argument even honored in the Xcodebuild command used in the Bot?