How to let NextDNS.io work with ddclient to dynamically update an IP address?

My dynamic ip address is updated by my router: an appliance running OpnSense router software. Version 22.7 is just released and they decided to replace the old DynDNS plugin with ddclient.

I need to convert this https://link-ip.nextdns.io/264248/4a8f74b76c9a... into a config that ddclient understands. After a few hours trying, I gave up try my luck to ask for help.

The config should be something like 
syslog=yes                  # log update msgs to syslog
pid=/var/run/ddclient.pid   # record PID in file.
verbose=yes
ssl=yes

use=if, if=pppoe0, \
protocol=dyndns2, \
server=link-ip.nextdns.io, \
login=264248 \
password=c2cf0659cc56559b629f53604b51ab9... \
proxy.havhos.net

Unfortunately, the above does not work. Also the server field only accepts FQDN or an IP address. Not URLs. So, I kindly ask a little help from your technical engineers to help me out here with the ddclient config.

Thank you in advance.

Met vriendelijke groeten / Kind Regards / Med vennlig hilsen,

Johan Havermans