Novice - Setting up VPN on router - Orbi RBR50

Alas, there are two parts to a Virtual Private Network (VPN)

• The VPN Host, which accepts connects from Clients and sets up an encrypted "tunnel" between them, which effectively shields traffic from inspection and hides the Client IP address.
• The VPN Client, many of which connect to a Host.

Netgear bundles OpenVPN Host software with Nighthawk and Orbi routers so that customers can connect to their home Local Area Network (LAN) when away.  Netgear does not include a VPN Client capability with any of their home routers.

One solution would be to install a third party firmware which includes this capability.  A programmer has written firmware for some Netgear systems, including the RBK50:

https://www.snbforums.com/threads/custom-firmware-build-for-orbi-rbk50-rbk53-rbr50-rbs50-v-9-2-5-2-35sf-hw.90954/ 

Another solution would be to install an appliance on the LAN which provides VPN Client capability, such as the GL-iNet

MT2500:

https://www.gl-inet.com/products/gl-mt2500/ 

or a similar product from Firewalla.

Perhaps I am mistaken..... How does "casting" video to televisions "work"? i.e.

• Does the user somehow bring up a menu on the device connected to the television and tell it which video to seek?
  (In this case, it's pretty obvious that the source IP address will be the public IP of the customer router.) ... or
• Does the user device "cast" the video stream fo the device, which passes it to the television.
  (In that case, it would seem that installing a VPN on the user device would fulfill the requirement.)