Can’t help with the Smok and not sure which Aegis/Geekvape model it is ? But on the Aegis is it possible you have turned the brightness down to the point you can’t see it I have done this. Take the tank or whatever your using off of it push and hold the fire button and using the +- buttons you can adjust the brightness from 1-100%….. Worth a shot anyway
You’ll also have to make sure it’s unlocked to do this press and hold the +- simultaneously for a few seconds to lock and unlock wattage.