The guide that PIA provides on their website assumes that all traffic should go through the VPN by default and you must select which devices and/or ip ranges that you wish to route outside of it. I would think that the guide that @wendell did is based on the same assumption but it’s been awhile since I watched it and I setup mine a couple years before that video.
The PIA guide has you duplicate all the WAN outbound NAT rules and then assign the new rules to the openVPN interface. So, all the traffic leaving the system is translated for the WAN and VPN by default (this doesn’t determine which interface the traffic leaves). You might try setting up the PIA outbound NAT to only translate the sources that you want instead. There are probably many different ways that it could be accomplished but I would think using policy routing with fire rules would be better though.
You would need to setup static ip’s for your 2 servers outside the range of ip addresses that all your other LAN devices use. Then setup an aliases that covers the ip address range for that segment of the network, then put a rule like the ones I pasted in to route all that traffic through the WAN gateway at the top of the list.
I selectively route things outside my PIA and I’m not a network professional so I can’t say that will work without testing it myself. I have setup bypass rules for specific hardware, ports, and address ranges. You can tell that any one rule is working by keeping an eye on the “States” column. You will see the number of states and the amount of data traffic that the rule has processed.
If you want those ports to be open even through the vpn then you’ll have to connect to one of PIA’s servers that allows port forwarding.