If you use Thunderbird ver 78.3.2, gContactSync extension will not work anymore. To fetch Google Contacts into Thunderbird, use the CardBook extension.
To install Thunderbird client, open a terminal window and enter the following command:$ sudo dnf install thunderbird <enter> To get the calendar working in Thunderbird, add the Lightning addon from Extensions in Thunderbird.
To synchronize Google Calendar with Thunderbird Lightning, open Thunderbird and install an add-on named "Provider for Google Calendar" by Philipp Kewisch. Follow the instructions after the install to grant permissions to your Google Calendar and synchronize.