You literally can’t see the trees through the woods when it comes to the ideal soil layer. Usually I go looking for knowledge online myself, but Youtube is full of it and also read a lot of untruths.
Linda Scott-Chalker is an American professional known for fighting myths and fake news in the field of agriculture. Usually she transforms dead ground into a new piece of blooming nature. They call it restoration. She did an experiment to show what the best soil layer is.
Her website is great because she tries to debunk some myths. So definitely worth taking a look there.
But this video is a masterclass of how the fork is really down. Thanks to research. So really worth it