Coding is something you will never truly master. It’s okay, nobody does. There is always something new to learn, always a way to look at a chunk of code and work out ways to make it better.
Your employers think of you as a wizard so they’ll keep piling on work until you burn out, not knowing your limits. So it’s not just about learning how to code, once you do that, you have to learn how to assert yourself.
I say keep at it until you learn how to thrive. It’s not a matter of talent, it’s a matter of putting in the time and effort to learn how everything works. Good news is that it’s really rewarding once you nail it.