Asus w OpenVPN Server Recommendations?

[Philoctetes]

I thought setting up my aging Asus RT-AC56U router as an OpenVPN server would be straightforward. No. AFAIK, even when choosing the highest levels of encryption, the .ovpn file isn't up to spec w requirements of the latest OpenVPN client. So, I'm shopping for a new router which will work as an OpenVPN server. No firmware updates likely for the RT-AC56U. Suggestions, please? Many thanks.