These books will help you learn more about PHP in detail and make you a better software engineer overall. These days, https://davorminchorov.com/how-to-stay-focused-in-web-development but if I were to start learning modern PHP today, I would definitely start reading more books, because they do have a lot more detailed content and theory rather than the video courses.
This book will teach you everything about object oriented programming and the different types of objects in PHP.
I highly recommend the DDD in PHP book first because it has some great ideas and examples about how to think, code and design complex long term apps.
This book will teach you everything you need to know about how to automatically refactor and upgrade your PHP code with Rector.