What makes you think it doesn't already do this? It works fine in clamshell on my M1 MacBook Air. But I am on Monterey and haven't tested on Big Sur.
@jdb8167 or anyone, can you confirm that, with an M1 MBA in clamshell mode, with a wired connection:
1. Single pressing the Touch ID button will start a shutdown machine?
2. Press and hold will bring up the Startup Options?
In other words there is no reason to take it out of clamshell mode except travel.
I wouldn't expect these to work with bluetooth only, no wire, but will ask.
Thanks.