I can access the Asus router webpage while away using the VPN. I can also access the webpage for my Z wave system while away connected with the VPN. I don't know what else to try to prove/confirm my iPhone and MacBook are connecting with the VPN. Something is not set right on the NVR or it could be my ISP.
I will ask again, what should the Preferred and Alternate DNS be set to?
Don't worry too much about the preferred and alternate DNS settings, they aren't particularly relevant to this VPN problem. If in doubt, use Quad9 (9.9.9.9), Cloudflare (1.1.1.1) and /or Google (8.8.8.8), your choice of preference order.
If you say that you can definitely access the web interface of your Asus router from outside your home network over the OpenVPN connection, that seems to prove that you have the connection sorted. However, without going back and re-reading through the whole thread, did you say that the NVR exposes an interface on the same subnet as that Asus router provides? If so, it should be accessible, if not, perhaps the NVR is configured to a different subnet?
There is the slight possibility that your ISP could be blocking connections, although your ability to reach the router web configuration pages seem to prove otherwise. Most OpenVPN configs by default setup the tunnel over UDP, port 1194, and that is best for various efficiency reasons, but you could also try setting it up over TCP, port 443 to test out the blocking theory.