I haven’t used dd-wrt with openvpn, but I have used openvpn a lot with my GL-mt1300 connecting as a client to my Asus-Merlin routers running OpenVPN servers. So I’m trying to see what is different to my setup. My MT1300 is on the -oops firmware, and I’ve just imported an .ovpn config for my Asus router into the MT1300. It connects just fine.

I’m a little unclear on where the “Additional Configuration” is for you. Is this client or server side? The key is enabling pushing the redirect of the default gateway on the client side, which looks to be correct on your server configuration. That includes in the server config “push redirect-gateway def1”, so in your log you should see something that says “received control message:” with that among the list. If the additional configuration is on the client side, I don’t know what that means. I would delete all three of those lines if they are.

Second, your log at verb 4 or 5 should be a crapton longer. Among other things it should be adjusting the link mtu to something larger than 1521 for 1500 in the tunnel. There should be hints.