Hassio not accessible from the external

Hi guys, duckdns has always worked to access my hassio from the external, but unfortunately I had to put a modem that via Wan connects to my Asus modem/router, so now hassio from the external doesn’t work anymore, but maybe I understood what is it, previously with my Asus modem/router I had problems with noip.com (a dynamic dns that I use to access on the modem/router functions from the external and to access the Windows remote desktop)
But initially didn’t work because in the setting of my Asus modem/router in “Method to retrieve WAN IP” it was set to local, so it took the internal ip of my modem and told noip.com that my ip was (for example): 192.168 .1.1, but changing this setting from local to the external I solved it, so I think in Duck DNS or NGINX Home Assistant SSL proxy there is function to use external ip and not local one, how do I solve this problem?