The imagick module is not required, and even seen as possible security issue. A matter of discussion on GitHub, but many, including us and some official Nextcloud appliances, chose to not ship it.
The other two modules are explained: If you don’t use WebAuthn, you don’t need them, as Jappe mentioned.
The first four warnings however should not appear. Can you show the output of:
cat /etc/nginx/sites-dietpi/dietpi-dav_redirect.conf
grep -E 'webfinger|nodeinfo' /etc/nginx/sites-dietpi/dietpi-nextcloud.conf
curl -IL 127.0.0.1/.well-known/caldav
curl -IL 127.0.0.1/.well-known/nodeinfo