Nothing wrong with your Sea Star steering.
This is normal and the higher you raise your motor the worse it will get. Steering torque is caused by the prop rotating partially out of the water. As your speed increases and the hull begins to lift the prop is partially in the water and part out of the water.
You can decrease the amount of steering torque by lowering the motor deeper into the water. The lighter the load in your boat the higher you can raise the motor and still maintain good hull lift. Drag is the enemy of speed. The heavier the load, the deeper you will have to run it to lift the hull to achieve good top speed.
Try this. Get up to top speed and note the steering torque on the wheel. Now start lowering the motor as you run at the same throttle setting. You should notice a decrease in steering torque. Watch your speed on the GPS while doing it. Did it decrease or increase? If it increased, you had the motor too high to begin with.