I haven't had that happen on iOS, but I have woken up in the night needing my flashlight just to find my phone applying a lengthy update. I have it set to download automatically and install manually now, I believe.
I haven't had any problems in at least 7+ years, but I work in coffee and I can remember at least two instances where an Apple update made half the staff late by turning off their alarms, myself included.
I like an amber booklite, it isn't as compact but the light is better for keeping in the sleep mode. We used those as our lights to help develop our child's sleep hygiene. Cupped our hands around the light part as we puttered around.
I do, in my nightstand. In the event of an emergency where we’re without power, I do not want to waste my phone’s battery power by using it as a flashlight.