Really sorry, I originally posted this in the wrong place

I’ve been doing a lot of independent thinking recently, and lots of it has led me to this forum; I am becoming more and more sceptical about the nature of the planet. However, one thing this journey has definitely taught me is to question what others might say and try to work out an answer for myself.

To my question:

It is my understanding that mainstream science believes the sun to be 93 million miles a way, and producing vast amounts of energy through nuclear fusion at its core, which occurs due to the extreme temperature and pressure, then releases energy from its surface as electromagnetic radiation (light and heat), which provides energy to the planet.

In my research of the flat earth model, the sun is believed to be a much smaller and closer light source, acting as a sort of spotlight on around half of the plane at once. My question(s) is, if the sun is much smaller than believed by modern science, then how can it produce enough energy for the earth, and is there another energy source that I’ve missed?

Feel free to let me know if I’ve missed something obvious (I didn't see anything answering my question in the FAQ, but if there is please let me know), or have explained something incorrectly, I’m fairly new here so any help is appreciated.