I have read many articles about WSL networking that try and sort DNAT and static IP and none that I've found seem to work or only work for some. So here is my attempt....
It seems getting port forwarding to work in WSL is not easy. I think WSL has unusual hidden network mechanisms and that confuses the matter. Also when WSL boots the WSL init mechanism gives the guest a random address, which is no use for static NAT
This worked for me. Try it yourself and let me know if I've finally cracked it !!