I like Udemy courses. I try out some of the exercises the Udemy instructor suggests. It is somewhat ok. But not quite useful because in real-life (actual projects), the complexity is much higher. And I will spend probably weeks doing a single feature. Which in an Udemy course is done within a few hours.
Also, in JavaScript, there are too many packages. So going through documentation is not very helpful. There is just lot of documentation out there. And it is not feasible to go through each one of them. And invariably, all packages have a downside. So, I use my intuition to pick the right package: popularity, ability to customise, etc. And most of the time, I write my own code.
If we write our own code, it is more rewarding. No need to read up docs. Rather be more creative in coding up stuff.
What I am looking for, especially for the UI, is not documentation on how to use a package. But rather guidelines on how to write good code. For eg, what is expected of a generic Button component? a) styling b) loading indicator c) animation etc. These things are not discussed in any course or found in any documentation. But something that we discover by writing our own code for stuff.