I believe the STB engine on the PC-24, an aircraft of which I have NO real knowledge of other than reading a glossy brochure, has an APU mode; reduced RPM and importantly noise levels.
The aircraft AFM will have any requirements for a pilot to be seated at the controls as part of the 'Limitations' section, for ground op of the r/h engine; regardless that does not stop the operator from obtaining a local CASA dispensation to operate in APU mode with no-one at the controls. Just present a safety risk analysis synopsis.