Retrieve via IMAC Terminal the WAN IP address of LBR1020 router when behind a CGNAT

I have a LBR1020 router and would like to know how I can retrieve via an IMAC Terminal session my WAN IP address from the router itself.

This because I am behind a CGNAT and my DDNS gets the CGNAT address and not my Routers IP.

Also then how to script this to update DUCKDNS online and in Home Assistant if possible via a script