What engine power setting is used during cruise?
At first, I was tempted to close the question as a duplicate, but then I could not find one that would address the point directly. But there are many questions and answers on this site which allow one to cobble together the answer:


Why are many jet aircraft designed to cruise around FL350-370?
Why has the maximum service ceiling of Boeing and Airbus products remained about the same for 30 years?
Why do jet engines get better fuel efficiency at high altitudes?
How much fuel does it take to start/land an aircraft, compared to normal flight?
What is the one-engine-inoperative maximum range flight configuration?


To save you to read through all linked answers, here is the gist of it: Jet engines are run at close to their maximum power during cruise, but their thrust is much less at altitude due to lower air density. Airliners want to fly as high as possible to fly faster for the same drag and to gain efficiency, and their designs are balanced to achieve reasonable take-off distances and good cruise performance at close to maximum thrust.