Finally got it working, turns out I'm somewhat dumb, I ended up using a port forward, but just had to limit the external port to the eth interface.
To be exact I just setup the port forward as usual:
With the internal ip address being the machine you are forwarding to (like a regular port forward)
Then in the advanced settings you set the "external ip address" to the interface that has your public ip (99.99% of the time it's probably a eth interface I believe):
This seems to work as I expect, but I suspect that it will block access to the router if you forward the same port that the webui is using for http\s access. For my setup this seems to work perfectly, and as such I'll mark it as solved, if someone finds a better solution feel free to chime in.