Google Pixel 7 & 6 Pro keep screen ON while viewing
If you are using a Google Pixel 7 & 6 Pro, then you can either use a screen time-out, after which the smartphone automatically turns off, or use the "Smart Stay" feature.
With the "Smart Stay" feature, the display stays on as long as you look at it. This is ensured by the front camera, which detects whether you are looking at the smartphone.