There are two kinds of programming languages: (i) where the official manual is clear and complete, and (ii) ones where it is not.
In a type (i) language you should read the manual while spinning at the gym and train yourself to be very fast to look up answers to questions like "how do I generate a random integer in the (3,7) range" in the official manual.
Books, blog posts, etc. tend to inject errors and also become stale over time. For instance there is a lot about Python 3.5 and 3.6.1 that you don't want to know. A Pythoner in 2021 could be working with anything from Py 3.9 to 3.7 or late 3.6.9. A book written to Python 3.7 is going to be a basically good foundation to work on, but I know Py 3.8 and 3.9 feature use is common in the wild and 3.10 is not far away.
If you learn the manual like the back of your hand, you can look up whatever version you need, what the changes are, etc.