For those not entirely sure about psychological aspect of the match, including Karjakin's strategy I was talking about, check a psychologist view on the subject:
https://chess24.com/en/read/news/a-psychologist-analyses-carlsen-karjakinFragments:
"Karjakin, however, demonstrated that he'd come well-prepared to the World Championship and
knew perfectly what he had to do: to defend as no-one else in the world can, so that the pressure of failing to win would begin to weigh on Magnus."
"Game 8. Magnus provoked Sergey on various occasions, attempting to get the game onto "his" territory, but the
Russian kept implacably following his own strategy."
"3. Following a strategy. This is the final ability that we'd like to stress with Karjakin, since he
remained faithful to the strategy adopted by himself and his team and in no circumstances deviated from it. They managed to grasp the ways in which they could triumph in the match, both on account of Karjakin's potential and the possible weakness of Magnus. That ability to set out a plan and follow it, without getting distracted by other factors, is truly noteworthy, and came very close to unsettling the World Champion enough to achieve victory."
"It may turn out that
emotional and mental control is one area in which Magnus can still improve."
"Karjakin, in turn, demonstrated a certain lack of ambition in some moments of the match, when he could have made the World Champion suffer more. It's possible that in the near future this match might be repeated, and in that case
Sergey will have to play with more energy in key moments in order to be able to get the better of his opponent."
I fully agree with the Author.