@timonus I just switched from external monitor + MacBook to a larger screen and clamshell, so lost my TouchID.
Bought a TouchID keyboard used on eBay for $50, pulled out the button and logic board, hack saw’d the button well so clicking still works, and hot glued it to the bottom of my desk. Works great!
(Only hot glued on tape, not directly to circuit boards, for easy removal)
Guide: https://gist.github.com/KhaosT/1406a6b6bea38f59e059c2afcb39d545
3D model if you want it in a case: https://www.printables.com/model/320000-standalone-touch-id-module-for-mac
Alternate model (no back for mounting under-desk): https://x.com/KhaosT/status/1523339671949873152
I first heard about this when Myke Hurley did it, which prompted this post: https://sixcolors.com/post/2022/07/touch-id-on-a-mac-desktop-deconstructed/