The web page seems to say that you have to jailbreak devices running iOS 14 or higher, which would presumably include the current iPad Pro models:
> If you are running iOS 14.0, 14.1, 14.4, or higher: UTM works if you are jailbroken or semi-tethered with Jitterbug, AltJIT, or Jitstreamer.
Presumably iOS 14 and later include security features that prevent you from running generated (JIT translated) code directly. I imagine that tethering to a development environment might allow translated code to be signed, or perhaps it supports code injection via the debugger interface.
> If you are running iOS 14.0, 14.1, 14.4, or higher: UTM works if you are jailbroken or semi-tethered with Jitterbug, AltJIT, or Jitstreamer.
Presumably iOS 14 and later include security features that prevent you from running generated (JIT translated) code directly. I imagine that tethering to a development environment might allow translated code to be signed, or perhaps it supports code injection via the debugger interface.