Enter Password Greyed Out after Update - macOS Monterey
I have the same issue as this post: Account Login Option Grayed Out - macOS M… - Apple Community
on a mac mini 2014. My keyboard is a Logitech MX Mechanical Mini. Before Monterey it worked fine, after the update the password field was greyed out though my keyboard was recognized fine, as I could change the volume. It may be a fluke, but switching the keyboard to "mac" layout by pressing and holding fn + i allowed me to log in.