Say you're landing on a 15,000 foot runway coated with ice. You want to keep
the plane going in a straight line without thrust reversers. Which is the
greatest contributor to yaw?

Engine torque

or

Thrust

or

Rudder?

Is their a difference from piston to turboprop to jet?

Why is it important to know this to keep the plane going straight?

At what airspeed does the rudder become ineffective?