Fix Your Forehand Backswing with Tips from Leylah Fernandez 

Na she just dropped the racket head

You are correct.

She has a very unnatural weak forehand, locked out straight arm forehand, very awkward

Sorry. You're wrong. She did right.

I agree, do a slow mo and she does drop the head yes, but its way behind where she said it should be

Well obviously they have larger backswings, but still swing through smoothly. I think shes more talking about the "double backswing" where you already have the racket taken back, then take another backswing, which can cause a late forehand contact.