This is due to the changes that Apple has brought in. The following link details regarding Catalina specific changes for smartcard - HT210541
Apple has changed the existing framework and mandated to use cryptotokenkit framework instead of TokenD which was used until Mojave release. The driver support to read certificates from smart card is provided by third party packages. However with Catalina, these are broken as none of the software providers are supporting it.Apple has very recently provided drivers for cryptotokenkit framework.