Pics might help. How does the steering feel without the servo in place? Try holding the servo horn where it would mount to the servo and rotate it to see if you feel a bind. Do so with the vehicle sitting on the bench as it would be driving. So don't use a chassis stand. Look at all the steering linkage and see if anything might be binding up.
Do you have a servo tester? If not, remove the servo from the rig but leave it connected to the receiver. Put the horn on it and use your finger to put a bit of load on the horn as you rotate it each direction. See if the servo feels strong both directions.
This is a good tool to have.
ICQUANZX Digital Servo Tester / ESC Consistency Tester for RC Helicopter Airplane Car Motor Throttle Display
https://a.co/d/gQoYqkL
Power supply for tester.
Tenergy NiMH Receiver RX Battery with Hitec Connectors 6V 2000mAh High Capacity Rechargeable Battery Pack for RC Airplanes/RC Aircrafts and More
https://a.co/d/eVp2K0a