Who would need to press the power button to actually turn off or restart the device, right?
The setting to change this is also pretty much buried under Settings -> Special Features -> Gestures.
(Yes, I have no idea why the Assistant is in German when the phone is set to English either 🫠)
It just asked me what it should do when I press the power button. Pretty painless, 🤷. End of the day it’s just another win for GrapheneOS though.