I work full time, and always go for a quick easy breakfast, on weekdays.
Usually it is just a coffee with a good glug of cream (virtually no carbs in cream), or
crustless quiche
ham and cheese slices
sometimes I have cooked sausages the night before, and just reheat them in the microwave
There are some great egg muffin recipes (basically just egg and veggies) on the internet, that can be made, frozen and then reheated in seconds in the micro.
Greek yog with a few berries
left overs from night before
Lidl protein roll, toasted
It takes a bit of a change in mindset, but once you have made the transition, breakfast gets much more interesting than boring old cereal or toast, and can be very quick and easy,