I recently purchased a 1999 Volkswagen Passat Station Wagon (1.8L). The issue i'm having is with all 3 door locks on the vehicle -- driver, passenger, and trunk. The keys i use to start the car does not fully enter the lock cylinder of the three external locks -- it enters about 1cm then stops as if something is preventing it from going deeper. I am unable to turn the key. The keys do work for the ignition and glove compartment.
According to the previous owner, he never locked his door supposedly only relying on the remote locking. I figured the issue then could be with the lock cylinders (tumblers?). I exposed the hole on the side of the door leading to the door lock cylinder screw and tried turning it. IMPOSSIBLE. It looks and feels rusted tight.

I then removed the inner door panel and metal frame to expose the backside of the screw. You can see it in the following photo:

I still cant get a decent bite in that screw. CAN SOMEONE PLEASE tell me a way to get the door lock cylinder out? My understanding is the screw must loosen. From the above photo i can try to work the apparatus which the screw turns but i'm unsure how it operates back here.
Any ideas on what i can do?
According to the previous owner, he never locked his door supposedly only relying on the remote locking. I figured the issue then could be with the lock cylinders (tumblers?). I exposed the hole on the side of the door leading to the door lock cylinder screw and tried turning it. IMPOSSIBLE. It looks and feels rusted tight.

I then removed the inner door panel and metal frame to expose the backside of the screw. You can see it in the following photo:

I still cant get a decent bite in that screw. CAN SOMEONE PLEASE tell me a way to get the door lock cylinder out? My understanding is the screw must loosen. From the above photo i can try to work the apparatus which the screw turns but i'm unsure how it operates back here.
Any ideas on what i can do?