You’re better off learning foundational knowledge. Languages are notations, not intent. What has been useful for me are Computation theory, Algorithms, Concurrency, Distributed Systems, Operating Systems theory, Practical system administration, Computer Organization, Networking,…
I do get language books, but only as a reference. For anything more advance, I usually read the sources.
You’d think someone would write about the tricks you learn breaking your teeth on the language though.
And they do, in random forum and blog posts though.