I have a Librem 15 (running Pop_OS 20.10/Heads) and a Librem Key. Heads works remarkably well. I haven’t gotten the Librem Key set up to unlock my LUKS partition yet (the script provided by Purism doesn’t seem to work with modern LUKS configuration schemes. I’m working on that, though, and will post updates when I get things updated).
However, I’m having a problem with GDM - It frequently takes between 2-15 unplug/replug cycles for the Librem Key to be found. It ultimately WILL be found, so I know that my configuration vis-a-vis SCDAEMON and UDEV seems to be correct. I’m not using this key for anything other than laptop authentication - I have apps on my phone and watch for HOTP/TOTP.
Is there anything else that I could check?