https://aviation.stackexchange.com/questions/35575/how-does-the-f-35-hover
"the lifting system itself moved by the F-35's engine. The pilot works at the pitch of the fan, meanwhile computer countermeasures how to maintain stability. The pilot itself could push a button or use voice-activating system to open the lift-fan's door."
So the blade pitch is under his control, but then the computer would determine how the nozzle in the back keeps it stable?
man that plane is very complicated , so many ways it can go wrong..
Harriers had just as much problems , but way more mechanical and it was ususally the pilot who kept them pointing in the right direction and up vs down. Analog.