With modern Windows devices comes Modern Sleep/Standby. Whilst great in theory, we still haven’t gotten to the point of slick mobile-like flows you might find on Android/iOS. This means that the device locking itself when you glance away is terribly inconvenient, and so users rightly complain.

There’s several Windows services that control this, depending on the firmware/model. Disable any of the ones you find:

You may also have to disable it in Lenovo Commercial Vantage.