I have some trouble with my iPad :
Since iOS 12, when I launch an app and set "guided access", the screen go to sleep mode after 20 minutes.
I use to set "guided mode" because my iPad serve as kiosk, on previous iOS there was no problem, the "guided access mode" was refering to "display, sleep mode : never"
My only solution for now is to back in time and restore iOS 11 but don't know how since ISPW is now unsigned;
Any advice , please ? I have tested everything...