Wan Port Dead [D-link DIR 615 (h/w:X1)]

I have a D-Link Router.

Model Number: DIR 615

H/W: X1

The WAN port of this router is damaged and is not connecting. It has 4 LAN ports, but they are rarely in use. I want to convert one of the LAN ports to work as a WAN port so that I can use the internet.

I want to install a 3rd party firmware to unlock additional settings that are not provided by the D-Link firmware, as there is no option in its default firmware to switch ports configuration settings.

I have searched on the internet but I am not able to find any solutions.

#Image of all the port sections.

#Image of the device.