You can literally no longer see the trees through the forest when it comes to the ideal soil layer. Usually I look for knowledge online myself, but YouTube is full of it and also read a lot of falsehoods.
Linda Scott-Chalker is an American pro and known for fighting myths and fake news in the field of agriculture. Usually she transforms dead soil into a new piece of blooming nature. They call it restoration. She did an experiment to show what the best primer is.
Her website is great because she tries some debunk myths. So definitely worth a look there.
But this video is a masterclass of how the fork is really down. Thanks to research. So really worth it