... sorry, put my answer in this comments box by mistake - now can't delete the comment!

Maybe there's a connection: SpriteKit will be using Metal.

Yup, I too checked on an intel mini.

I've logged a bug report: FB9966514

so it’s all a bit random: none of the stuff I’ve been working on has done this since I switched to Rosetta builds…. Must be down to the graphics card spec…?

I also had this problem, the solution was to clear the trusted machines in the phone's Developer Settings, connect my MacBookPro to the phone's hotspot, add a device in the "Devices & Simulators" window. Then connect the USB-C > Lightning cable, select the iPhone in the list on Xcode's Devices window, click next and then respond to the "Trust This Computer" alert on the phone. Only with that combination did I get it to work! Took an hour of fiddling :(