I feel like a significant part of learning a new language is also learning the standard library alongside the new syntax. Especially because these can be quite different between different languages.
Learning the standard library, and the patterns it has encouraged in the community, takes years and is a moving target. Even a basic (accurate) "feel" for things generally takes weeks, regardless of how "simple" the language is. You might be able to produce code prior to that, but being able to predict where something should be, or how to find it, takes time.
OMG, you are so right! I feel the same. Knowing what the standard libraries bring (or don't bring) for each language that one learsn is immensely helpful. Sometimes this helps me decide which language to use for particular use-case/project, or sometimes it helps me better understand what the level of effort will be for a project if i use langugae X vs language Y, and on and on, etc. I feel like a tour of each language's standard libraries is a must when learning a new language; or at least a cusrosry review of the most important and/.or most often used functions, etc. of said standard libs.