Calibration troubles and Power very inaccurate. Resistance is also very heavy and doesn't register power accurately

This is my first smart trainer and Im very, very disappointed. When comparing power measurements to my bike computer and crank the wattage difference is anywhere from 20-45W off! The resistance is also sooo off. The flywheel will get very heavy and start to drag. Nothing but headache with this trainer... anybody have the same issues?