One of my painter friends said that he wants to dive deep into his skill tree. I like that framing.
Any skill set whether it be painting, writing, or product management has a skill tree. When starting off, you don’t see many branches. But once you start to learn and develop a skill on any one branch, you begin to see more branches. As you gain expertise, you see nearly the whole tree and explored many branches.
In short, mastery requires going deep on the skill tree.