About Process IPv4 or IPv6 route

[VeinGuo]

Remove redirect-gateway def1 in the ovpn configuration file
The routing table does not add the forwarding of the gateway by default in OpenVPNAdapter

In macOS, Win and Linux clients, it is implemented to handle IPv4 or IPv6 gateway default route
https://github.com/OpenVPN/openvpn3/blob/67172a582c1598f1e30fbd3a246251d60618416c/openvpn/tun/mac/client/tunsetup.hpp

NEPacketTunnelNetworkSettings doesn't add it by default.