Yes. Even if you would be able to select it, you would right stumble into a bug. A WebDAV storage opened with your file browser (Nautilus) uses in the background GVFS, which is not compatible with Cryptomator.
davs is just the communication protocol, davfs2 is a programm in your linux distro. A good how to ca be found in the nextcloud docs:
https://docs.nextcloud.com/server/latest/user_manual/en/files/access_webdav.html#creating-webdav-mounts-on-the-linux-command-line