CAC reader on Ubuntu

I recently got a System-76 laptop running Ubuntu 22.04. I am trying to get a CAC reader to work following the absolutely lovely walkthrough posted by M-Pepper here: https://github.com/M-Pepper/linux-cac-walkthrough . I cannot get opensc to register in firefox, using pkcs11-register or manually. When I use the pkcs11-register command, it shows that it added OpenSC to ~/.pki/nssdb/pkcs11.txt, but when I go into firefox and check security devices (settings > Privacy & Security > Security Devices), there is no OpenSC; the only thing that shows up is NSS default devices and OS devices. When I try to add a security device manually through that same menu, I get an alert saying Unable to add module. I initially installed OpenSC from apt, but then I removed it and built from source so I'm running 0.25, on firefox 129.0. I alternatively tried a setup script from another source that used Cackey, but that also failed and I ultimately removed Cackey and its associated packages. I'm not sure where to go from here... please help!