How do I stop the screen dimming and the phone from going to the lock screen?

I am using an iPhone connected to a Mac connected to Windows. I am using the iPhone for app development. Every time, I look around to look at the phone, it has gone to the lock screen and turned off the display. And I then have to enter the pin code. I need the screen to remain on for longer. Any of these solutions would work. I don't care if the screen burns out or if the battery will discharge faster. In order of decreasing desirability - Don't turn off while the USB is plugged from it to the Mac - Remain on for longer, say 30 mins - Remain on permanently --- I am using it to write two different sort of apps. 1. PWAs (Progressive Web Apps) - In this case the connection is Safari. This is what I am working on now. 2. Regular App - in a few months time I will be writing normal apps - In this case the connection will be XCode. But this probably won't bother me that much as the changes will be less frequent.