Hi there! My name is XXXXX XXXXX X'X a BMW tech.
This sounds like your starter has failed, honestly. I'd try to locate a local BMW shop with good diagnostic capabilities though so they can rule out it being the other two possibilites which would be the EWS (internal security code system that prevents the car from starting without the key) and/or the ignition switch.
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If you have any other questions, please don't hesitate to ask!