You car probably has a drive-by-wire throttle system. That means that unlike most 20th century cars where stepping on the pedal cause a cable or rod to directly move the throttle valve, with yours there’s no physical connection between the accel pedal and the throttle valve. It’s done instead by the engine computer electrically sensing the accel pedal angle, and then commanding an electrical actuator on the throttle body to open the throttle valve. So something’s wrong with all that, most likely either the pedal angle sensor or the actuator.
Does this seem overly complicated to you? I mean all that’s necessary is to move the throttle valve. I think the reason the car designers are using this system is b/c there’s a variety of things that must increase the idle rpm to avoid the engine stalling; i.e. low coolant temperature, turning on the headlights, turning the steering wheel, etc etc. So instead of requiring a separate mechanism for each of those, they decided to just deal with it once and for all by using the computer & an electrical actuator to adjust the idle speed as required.