I think this is the key to success. One of them is. If you don't follow this rule, burnout sets in for anyone. However, in the case of Teheran, it was the coronavirus that hurt him - that is another story.
I'm not sure I can answer that question. Every person has a different motivation. I think if he really wants to, he will show the previous level of play.
He probably wants a change. I think he will be able to show a higher level of play in his new position. But that is not a fact. Maybe he just needs more motivation?