Note
This configuration is untested as some values have been changed and I'm not running this container anymore.
When running other containers as the same user you might want to prefix the names (like nextcloud-mariadb.container)
Create passwords for MariaDB:
echo -n "msql root password" | podman secret create nextcloud_mysql_root -
echo -n "msql nextcloud password" | podman secret create nextcloud_mysql -
Open port 5080/tcp in your firewall or add it to your reverse proxy