Can't get port forwarding to work no matter what.

Hello, for the past week I have tried just about everything out there to get port forwarding working. So far, I've tried:

-Setting the port forward (obviously)

-Following the guide on the Xfinity page

-Scouring the internet for answers 

-Resetting the router

-Factory resetting the router

-Ensuring there is no static IP

-Re-installing windows on my device 

-Releasing the Ip on my device and renewing it

-Setting ipv4 as priority on my desktop

and more

There has not been a single hint of port forwarding actually working and the current side-issue is now that I've released the IP again, the XFi webpage shows the wrong IP (10.0.0.57) instead of (10.0.0.108).

What am I missing? All I haven't done so far is replace the router itself.