I’m going to give an annoying answer to complicate things. You might be fine to do it without eating a breakfast before. Here’s my n=1 example:
I finished eating last night around 8pm.
I started my workout at 11:30am this morning. Nothing to eat before, just coffee. I had a big glass of electrolyte-mix immediately before my workout and just water on the bike. I did Galena -2 and then added an hour of endurance afterwards:
Obviously I eat a lot after to ensure sufficient nutrition for the day. My power has been progressing well.
This is a bit of an experiment for me to see what I can do without eating before the workout as time restricted eating (I prefer to call it this over intermittent fasting) helps me stay on top of my weight . At some point of intensity and duration I’ll need to eat before and during.
So not necessarily the end of the world if you can’t manage breakfast before. But what works for me doesn’t necessarily work for you and vice versa!