Another super late bump to this post, but did this ever gets resolved? I am once again having the same issue on an Asus router (AX68U) and I am unable to port forward at all. The ports are forwarded fine on the old router. Getting the same IP from the ISP, not CGNAT, port forwards are listed...
Yup, after the factory reset, all I did was go through the initial setup, change the IP and DHCP range, then port forward the 2 ports. (new here so I'll assume that's what you meant)
I'm on an RT-AX58U and on asuswrt-merlin 384.19. I also tried on stock firmware and from a factory reset. Same issues.
I'm trying to port forward the following:
Before anyone asks why I'm forwarding these, it's for a reverse proxy (a LetsEncrypt+nginx docker on my NAS). It's for accessing...