Thank you for your answer.
With 7.01.4 firmware, rules are displayed, even if they are two :
root@Teltonika-RUTX09:~# mwan3 rules
Active ipv4 user rules:
568 101K - balance_default all -- * * 0.0.0.0/0 0.0.0.0/0
0 0 - balance_ADSL all -- * * 10.0.0.240 0.0.0.0/0
0 0 - balance_ADSL all -- * * 10.0.0.241 0.0.0.0/0
0 0 - balance_4G all -- * * 10.0.0.148 0.0.0.0/0
Active ipv6 user rules:
124 19467 - balance_default all * * ::/0 ::/0
However, even if the rules are visible, there are not applied...
Do I have to wait a bit for the rules to become active?