I've mostly worked with Python so far, and my best companions have been the Python tutorial (https://docs.python.org/3/tutorial/index.html), the library reference (https://docs.python.org/3/library/index.html) and the language reference (https://docs.python.org/3/reference/index.html).
I was very surprised to see that on ruby-lang.org there is practically no equivalent o the Python tutorial. The closest thing is the on-line version of the pickaxe book (https://ruby-doc.com/docs/ProgrammingRuby/) which is about Ruby 1.6, released in September 2000.
There are a myriad of other small or smaller resources (koans and stuff) but no just-sit-down-and-read-all-this document.
So the question is... Why is ruby so poorly documented? How is one supposed to learn ruby nowadays, properly ?