The thing that really got me open to both cooking broadly and controlled experimentation was this book, which was a gift from my wife.
As the name Twelve Recipes suggests, it sticks to the basics and breaks them out into different categories (chapters include eggs, beans, pasta, vegetables, etc), starts with some very specifically-articulated recipes to begin with, and then uses that as a launchpad to provide a framework for experimentation.
I like this cook called Twelve Recipes by Chef Cal Peternell who was horrified when he realized he hadn’t taught his college-bound son how to cook. It’s geared to beginners and he gives descriptions of techniques and recipes like he’s talking to you, which is really helpful. The idea is that if you master 12 recipes from the book, you will always eat well and learn the techniques to cook a huge range of things you can riff from the basics. Recipes are simple, delicious and doable with minimal equipment.
This is my favorite beginning cook book: https://www.amazon.com/Twelve-Recipes-Cal-Peternell/dp/0062270303&ved=2ahUKEwjig6jh5ZTsAhUQK80KHU5eCvMQFjALegQIDhAB&usg=AOvVaw09tEhNiIoUaDkxruDW2V0Q
It's by one of Alice Waters' disciples (so think farm-to-table, elevated home cooking). It started as a list he wrote for his son who was going off to college of twelve things everyone should be able to cook well. For the book, he expanded it into twelve chapters with several recipes each. One is on tomato sauce and another is on other pasta sauces. Both chapters are excellent, with not just recipes but tips for how to improvise well. He has an excellent voice that is wry without being overly witty. Highly recommend. They had it at my local library.
Has anyone mentioned Good Eats yet? (kidding)
One book which is a nice approach to your exact situation is Twelve Recipes by Cal Peternell, a chef whose kid was about to go off to college so he wrote out a small collection of twelve recipes that were staples in their household which he thought could arm his kid well enough to get started out there on his own.
He ended up elaborating on everything, often guided by the questions that his kid called home with when trying to figure out exactly how they would always roast that chicken at home, etc.
It doesn't attempt to be an encyclopedia, but there's plenty of those out there. I'd give this a look, there's a lot of good advice in it.
If you're willing to invest ($7 used) this book is a great way to start thinking about how to cook.
Try 12 Recipes by Cal Peternell. Fun to read and some good tips.