Are you using an adjustable gap spark tester?
Did you remove the top cover an disconnect the coil kill wire? Did you watch the video that was sent? Missing some diagnostics on your end.
A sheared flywheel key on a rider is very uncommon unless the flywheel was left loose. Even then it would show fire but would be out of correct time.
Does the magnet on the flywheel attract a screwdriver blade really well? Is the air gap set?