A much simpler solution is to buy the GL.iNet GL-SF1200 (https://www.gl-inet.com/products/gl-sf1200/ - costs only $30) which is powered by the opensource OpenWRT router OS and offers VPN support (both as client or server) with built-in OpenVPN or Wireguard. Other costlier GL.Inet routers with more CPU power and more RAM are also available.