Hello! I figured out how to sync Gnome Contacts and Gnome Calendar without installing Evolution.

This method is proven to work on Fedora 41 Kionite (KDE).

Install gnome-online-accounts and the GUI gnome-online-accounts-gtk.

Next, run gnome-online-accounts-gtk. Click to add a WebDAV account.

Fill in server address http://localhost:37358, username, and password. You must fill in the "optional" calDAV and cardDAV server addresses as http://localhost:37358 All existing calendars and address books will be synced. You must remove and re-add the webDAV account for new calendars and address books to sync.