So…
<VirtualHost *:80>
ServerAdmin master@domain.com
DocumentRoot /var/www/nextcloud/
ServerName nextcloudXXX.duckdns.org
ServerAlias www.nextcloudXXX.duckdns.org
Alias /nextcloud "/var/www/nextcloud/"
<Directory /var/www/nextcloud/>
Options +FollowSymlinks
AllowOverride All
Require all granted
<IfModule mod_dav.c>
Dav off
</IfModule>
SetEnv HOME /var/www/nextcloud
SetEnv HTTP_HOME /var/www/nextcloud
</Directory>
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>