Thanks, I have managed to set it but only if cacher is set as netVM for the qube.
If any other qube is set as netVM, the error is thrown
Error
Err:1 http://HTTPS///deb.debian.org/debian bullseye InRelease
Connection failed [IP: 10.x.x.x 8082]
Is it possible sys-whonix for example to be set as netVM for the qube, yet it to updates via apt-cacher-ng?
Or, I am missing something in configuration?