If he does want to work hard, then why can't he work hard trying to do what is being asked of him? Okay, he may be asked to dumb down his forward runs but his form before Benitez was on a downward slope anyway. His crossing, set pieces and FKs had died out of his game. So the only person he should be upset with first is himself before he can take issue with the manager. I don't like approach my Operations Manager takes in half the decisions which affect my work, but hey I am not gonna use being 'ill' as a reason to not come to work just to make my point. You're paid a decent sum to do your job, so is Digne so if you think you're better than what your boss asks of you, then the boss has every right to make his authority clear and discipline you, just like Arteta did with Aubameyang. Plain and simple.
And likewise Digne can't take issue with the club if a new LB is signed. If he is motivated enough to prove the manager he's still the player we know he can be, then he'll fight for his place and keep the newbie on the bench. If not, then he will be move on.