Does anyone have experience doing this? Site with ER605 has CGNAT, while Sophos XG Firewall has public IP. Both has support for IPSec VPN, but I don't want all traffic to go to Sophos, just lan traffi

Hi. I've setup this LTE router as my backup source of internet. I've plugged a sim card to it, and it receives a public dynamic IP address. I want to pass that IP address directly to my firewall. Is i