In most sports if not all having the appropriate/ best genetics is the likely the biggest help in reaching
Top level.
Though no denying if you add in efficient & effective training it will be of immense benefit
Likewise diet & rest recovery.
I agree there is an awful lot of pseudo scientific trainers out there & just make stuff up to either
Appear knowledgeable or different / cutting edge.
You can’t reinvent the wheel - you can add a tyre & put air in it to improve its performance.
A good book is "Running with the Kenyans". It's about a middle aged guy from England who was a good runner in college but never great. He felt he never achieved his full potential in college due to outside factors like partying and other factors. Kenya is where the best distance runners come from so he wanted to move to Kenya and learn their secrets. He moved his family there. He immersed himself into the running scene there. What was their secret? Technical intervals? Scientific cycles of training? What was their secret diets? So many questions arose.
He found out some stuff. Most of the runners ran without shoes because they couldn't afford them. When they won some races and showed potential they got agents who are looking for their own wallet enhancement getting them running shoe contracts. It became a status symbol to have new running shoes to train in. Truth be told they could run without the shoes.
The biggest thing he found was they woke up prior to dawn. They ran long distances like 15 to 30 miles a day. After the run they would all find a shady tree and take a nap. They ate very little to no meat and ate one or two times a day. They were motivated to get a car, house and land for a farm. Many having achieved that objective lost their motivation to run hence the constant turn over in Kenya superstars.
So what he found out was the secret was a work ethic and God given innate potential. Nothing scientific. The British author went on the run the fastest marathon of his life.