Look deeper into the recipes and think about the process. Why do they have you put the butter in the pan, wait for it to sizzle, and then put in the chopped onions, long before the mushrooms? Because the onions need longer and more intense heat to break down to that lovely translucent phase. And juice comes out of them that mixes with the butter, so when you put the mushrooms in for the last 5 minutes, they get coated with the yummy onion/butter goodness. All cooking is chemistry. From how you cook a specific material, to the flavor profile of the final dish, everything is just chemical processes. For me, this makes cooking really simple. Carrots, onions, potatoes, and other root veggies go into the broth first, because they are hard and will take longer to cook. "Soft" things, like mushrooms and bell peppers and chicken go in later, because they don't need to cook as long. Watch the Netflix TV series "Cooked", and then read his book "The Omnivore's Dilemma". Cooking is best when done simply with great ingredients, and he does a brilliant job pounding that fact home in a really enjoyable way.
To add: protein and cook time is protein specific. Chicken cooked all day will be dry. Beef cooked all day will either become tough or fall-apart delicious depending on other conditions. Shrimp should be cooked until just barely done and no more. Squid must be cooked under two minutes or over an hour; in between it becomes rubber bands. Scallops are best seared quick and hot; pork is best slow and low. Skate? ...skate I have fucked up four times. That there is restaurant food.