My point is that the motor isn't working and you need to figure out why. I would use the working code to try and eliminate possible causes.
The voice recognition is a separate issue: it may be that it has trouble with your accent. Perhaps there's background noise (I assume that there's a baby around) or you're not facing the microphone.
Also, I wouldn't be surprised to learn that the videos you saw were each the best of fifteen attempts. If Alexa, with her millions of dollars worth of cloud computers, AI and machine learning algorithms can't understand me, I don't expect that little thing to be foolproof.