VPN router Behind A router

[Isramir]

Hey there guys, im not interely new to networking, but i would'nt consider my self more than a noob either. I am in the works of creating my homelab/media server setup. I want to setup some of my equiptment behind a VPN connection. i have purchased a subscription from PIA already. What i want to do is to setup a router connect a switch to it and make any client that connects to that router/switch send all the data thrugh my PIA VPN. that router/switch would be connected behind a regulare router where the rest of my devices would be connect. The reason i want this is to enable my smart TV and laptops to go around the VPN so that i can watch netflix without getting the "sorry it looks like you are behind a vpn" messages from netflix, while the rest of my devices can privatly acces the internet through the VPN.

I have shit loads of equipment so hit me with suggestions. I have a custom router with 4 lan ports that i can install whatever router software is easiest to do this with (pfsense, monowall, dd-wrt, open-wrt).

My main router is a simple d-link archer c7 router, this is the router where there should'nt be any VPN tunneling on.

I just don't know how to go about it, so i am open to suggestions.