I suspect you've lost sight of the original challenge: to get CSN Philly outside of a Comcast Philly account.Now..you use your cable credentials...in the future it will be like netflix or peacock
Authentication (using your cable credentials) implies that your (v)MPVD TV subscription (assuming that you have one) includes CSN Philly. I'm reasonably certain that anything outside of a Comcast Philly account (or maybe a Cox Philly account if such a thing exists) won't get you CSN Philly. How does changing your IP address by using a VPN service address that problem in response to that challenge?
For example, if I were to subscribe to my local Comcast TV offering, my RSNs would include ROOT Northwest, Pac-12 and NBC Sports Northwest. I'm fairly confident (though I can't test it) what is available to me wouldn't change to a different market if I simply changed my IP address. I would guess that the chances are better that I wouldn't get any RSNs at all if I were to use a Philly IP address.