iPhone 13 Pro Max unusable under the sunlight in summer!

I have been using the iphone 13 pro max for a few days on vacation and I noticed that after about 5 minutes, the screen starts to decrease brightness, and at 7:30 the screen drops to an unacceptable brightness level, such as to make the unusable device. the smartphone returns as bright as it should only after leaving it in the shade for at least another 7 minutes. Not my case, but a friend also has the exact same problem. Definitely not acceptable.