EdgeOS: request for help to limit the usage of NextDNS services on eth0 EdgeRouter port

Good evening,

I am new to the community, I use the free NextDNS service with satisfaction since V. 1.8.3 (then V. 1.34.2, 1.35.0) on a EdgeRouter lite3 in firmware 1.10.11 . I am a subscriber of "Orange Fibre" in France in Paris.  The router replaces provider fiber modem for the Internet connection and ensures the link to the TV decoder (up to date, state of the art configuration). I keep by obligation the Orange Livebox behind the router on the eth2 port for the telephony service which does not respect the SIP standards.

I installed the package for EdgeOs without worrying about anything else and everything worked perfectly until last June. Since the phone service doesn't work even though the Livebox indicates that all the services are working properly. I did not change anything in the configuration of the EdgeRouter, and the French community at the origin of the configuration does not report any new change ( lafibre.info ). I am afraid that this failure is related to a DNS server substitution. The proprietary TV and VOIP services doesn't work outside the Orange DNS.

I'm currently in version 1.36.0 with this basic configuration
:~$ nextdns config list
report-client-info false
use-hosts true
config 4cd79c
cache-size 10MB
max-ttl 5s
setup-router true
auto-activate false
cache-max-age 0s
max-inflight-requests 256
discovery-dns
bogus-priv true
timeout 5s
listen localhost:53
control /var/run/nextdns.sock
log-queries false
detect-captive-portals false
hardened-privacy false

I have browsed the wiki but I can't find enough information to limit NextDNS services to my local network eth0 LAN SWITCH 172.16.xxx.yyy for the internet connection or to force the dns from the EdgeRouter config on the ports eth2 LIVEBOX VoIP 192.168.2.1 .

I thank you for any help you could provide.

Kind regards