Forward Traffic To Wiregaurd Proxy

I have a iPhone using the NSSurge app that only supports Shadowsocks but I want to connect to a Wireguard VPN. So I am trying to setup a server that will run a Shadowsocks server and connect to the Wireguard VPN then forward traffic that goes to the Shadowsocks server to the Wireguard VPN. The Wireguard client creates a network interface (wg0) so I am trying to figure out how to forward traffic that goes to the Shadowsocks server to that interface.

Diagram