Restrict routing through OpenVPN

I have a VPN setup on a AR300M where the config states
route 10.8.0.0 255.255.255.0
not route gateway
I only want traffic to that range through the VPN all other traffic can goto the default gateway on the WAN.
This works as intended on teltonika routers and in the windows client so i can only assume its something specific to the GLiNet configuration.

Maybe you can use vpn policy?