@ohmykomu 

Hi,

Not every router that TP-Link sells has the VPN Server feature and yours is apparently one of those that don't.

I think of the current models the Archer C6 and C60 would be about the cheapest models that offer a built-in VPN server.

That's a bother.... Could I install openwrt on it instead to get around this and make it vpn compatible? Warranty isn't an issue, I just need it to work as I can't use my VPN app on my phone since it drains battery (surfshark+ old phone.)

@ohmykomu 

Ok, it seems I have misunderstood your question. Sorry. 

So what you actually want to do is to use your Archer C20 as OpenVPN Client to connect to Surfshark's VPN servers?

Support for the OpenVPN Client feature is still very scarce on TP-Link's home Wi-Fi routers. I only know of the Archer AX20 to have it.

As for OpenWrt. I see there are snapshots available for the Archer C20 V5, but you would have to check on your own how to install it on your router without "bricking" it.