Figma is a pretty basic tool, so what usually separates the beginner and a pro is general design skills and knowledge, not the knowledge of every intricate Figma hack. Craft > Tools.
What do you term as advanced? Writing Plug-ins? It’s a layered tool you can pick up the basics quite quickly, but there are deeper and deeper layers of complexity a lot of it due to the historical evolution - for example smart layouts vs auto layouts vs grid layouts and constraints.
I read the help for a lot of advanced knowledge. Also you pick a lot up on forums like this helping people solve their issues or seeing how problems were solved and looking at examples. There is a whole community site full of stuff to explore too.