#3 is also sometimes not a problem, many devices work with a bit lower or higher voltage. It’s because the DC to DC converter that is used to control the voltage for the device itself is tolerant enough.
Sometimes devices are multiple volts tolerant with the caviate that the components get warmer with higher input voltage and therefore the device could have reduced life expectency. If the devices where not tolerant especially for lower voltages a slightly bad cable or a long cable could drop the voltage enough so the device wouldn’t function.
#3 is also sometimes not a problem, many devices work with a bit lower or higher voltage. It’s because the DC to DC converter that is used to control the voltage for the device itself is tolerant enough.
Sometimes devices are multiple volts tolerant with the caviate that the components get warmer with higher input voltage and therefore the device could have reduced life expectency. If the devices where not tolerant especially for lower voltages a slightly bad cable or a long cable could drop the voltage enough so the device wouldn’t function.