It is true that blue light can disrupt our natural circadian rhythms, though the title of your post could be misleading, as “electronic devices keep us up at night”, could be interpreted as an issue with phone addiction or the EMFs could disrupt our sleep.
The source you used to find these facts is reliable. It tells us that healthy adults follow a 24 hour sleep wake cycle, and that, “when the sun rises in the morning, your body produces cortisol, a hormone that makes you feel awake and alert. As daylight fades, the body releases another hormone, melatonin, that produces feelings of sleepiness”, and that devices like computers and phones emit blue light, which has been proven to “reduce or delay the natural production of melatonin in the evening and decrease feelings of sleepiness. Blue light can also reduce the amount of time you spend in slow-wave and rapid-eye movement (REM) sleep, two stages of the sleep cycle that are vital for cognitive functioning” (Sleep Foundation). Blue light is helpful to wake us up in the morning, and can “boost attention, reaction times, and mood” (Harvard Health). It is true that spending time on devices before bed increases the time it takes us to fall asleep, and children are especially susceptible to sleep problems stemming from using devices with blue lights before bed.
Additionally, “Harvard researchers and their colleagues conducted an experiment comparing the effects of 6.5 hours of exposure to blue light to exposure to green light of comparable brightness. The blue light suppresses melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much (3 hours vs. 1.5 hours)” (Harvard Health).
https://www.sleepfoundation.org/how-sleep-works/how-electronics-affect-sleep
https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side