first off if you plug in any switch normal or AutoRCM it will auto power on if connected via AC Adapter or USB 3.0 Port via USB-A to USB-C cable... theres a trick to power a normal switch of while connected via AC or USB-A to C not sure if it applies to AutoRCM but... While the switch is on plug in the AC adapter but for checking rcm status use usb-a to c via a usb 3.0 port obviously power off the switch via the power off menu with the "sleep, restart, power off" from holding the power buttion now DO NOT disconnect the usb cable you should see after it powers off the little battery icon briefly in the upper left corner wait till it disappears now try sending a payload if it failed congrats its not stuck in autorcm you will have to power it off this way or use the mod menu as suggested.