Replacing akonadi by caldav and carddav for G sources sync

For many years akonadi is a nightmare about synchronizing Kaddressbook ⇄ G contacts and korganizer ⇄ G Calendar.

I know that you can use the protocols Cardav and Caldav to access to G contacts and G Calendar.

I try to use the akonadi engine about caldav and carddav.

What is the good url for accessing to G Contact and G Calendar ?