When you plug the wheel in, does it spin left/right/centre on its own?
If it doesn't then this indicates that the power supply that came with the wheel is currently not connected - the power supply is required for the steering and force feedback to work.
If the wheel does spin when you connect the USB, then check to make sure that you're running the correct version of GT7 for your platform. If you try and run the PS4 version of GT7 on a PS5 then the steering function can fail.