Could you use a CCD to take a print or palm scan to not require contact for auth? My mental model on this is Eufy locks that perform a vein print. A 720p sensor seems sufficient.
https://www.eufy.com/familock-s3-max
https://www.ubisecure.com/authentication/finger-vein-biometr...
https://en.wikipedia.org/wiki/Vein_matching