Turning off the display has nothing to do with battery. All the dashcams need you to provide power via 5v USB cable.

Wifi is an important feature, since it makes it easy to change the settings and look at the files.

Below is a good basic cam, just turn off the display.

https://www.amazon.com/Blueskysea-B2K-Dashboard-Capacitor-Detection/dp/B08L12YFCZ?