Workaround for Missing nat loopback of ISP router

Hi There,
I use a cascade of ISP router for Internet Access and Turris Omnia Router.
It seems nat loopback is no more available on my ISP router.
I provide web content accessible from the Internet and using no-ip for dynamic DNS.

All i want to do is to resolve requests when i am Inside my WLAN connected using the external hostname.
For example currently xxx.ddns.net cannot be resolved from WLAN, but from the Internet.

Is it possible to Solve that on the turris omnia Router centrally by Software or better by configuration?
I dont want to adjust /etc/hosts on each Computer in my WLAN.
Thanks alot for suggestions.
Regards,
Ken

The hints module of knot-resolver can be used to override DNS records for some specified names.