Mobile app: Option to keep screen/display always on

I usually have either my cellphone or tablet (iOS) on and showing my current Dynalist of items, but after my system configured timeout expires, the screen dims and then turns off. Which is normal, of course. However I know that apps can be configured with a “display always on” mode so that this won’t happen while the app is in the foreground. I think this would be a super simple option to implement for those who don’t want to have to keep tapping the Dynalist screen every five minutes to keep it on.