RT-AC88U Run through OpenVPN client into my own OpenVPN server?

I would like to know if I can setup selective routing for all devices in my network to be run similar to the third party client openvpn. I understand if you use a third party for the client side through openvpn, all devices are individually controlled. I currently have the router setup with an open vpn server, but running that way, each device requires its own software and some of the devices are not setup to support openvpn software ie:Amazon firestick.

Is there are a way to have all of...

RT-AC88U Run through OpenVPN client into my own OpenVPN server?