HELP!!! Im having the same issue, touch screen becomes unresponsive on Surface Pro 8 just purchased yesterday. It works fine for a few minutes, then for no reason the touch screen stops responding and nothing fixes it other than a reboot OR closing the screen onto the keyboard (which does not come with the device, so those folks that dont have a keyboard will not be able to do this!). Simply turning the screen on/off using the power button does not fix the issue.
This Surface Pro 8 is running Windows 11, version 21H2 (OS Build 22000.348) - this is the latest with applied patches.