The problem with RoR is that it's an all-encompassing framework. It gives you a huge collection of things you typically don't need — entire major layers like the database are frequently completely irrelevant to projects. This isn't just true of small projects, but can often extend to a large part of a career.
One of the grave dangers that older/wiser programmers have learned is to stop trying to pathologically "drink the entire river". Programming has a constant deluge of new frameworks, tools, and publications coming out, and it's easy to fall into the trap of thinking you need to know, well, everything. I know a lot of 'aspiring programmers' who accomplish next to nothing precisely because they waste most of their time reading about programming instead of actually practicing it. It's sadly rather similar to 'aspiring writers', or any other craft — some reading is helpful, but not when it crowds out the actual task it's meant to teach. Life is short, and you have a choice between "actually making things" and "doing prep work for making things". That's all reading the docs is — it's just prep work. It's completely useless unless it parlays into actually accomplishing things.
There are semi-rare cases where some language/framework is actually teaching you new fundamentals and is worth deep-reading to gain core skills as a programmer. Haskell broke new ground. Lisp was enlightening. Smalltalk was a worthy historical study. Rust is genuinely changing things. Unfortunately, Rails just isn't special.
When I was considerably younger, I used to pathologically do this — I used to buy books on programming, and read them like a school textbook "exam cram". I read entire books on languages (like Perl) that ended up exiting the zeitgeist before I ever did any work in them — and I now have no reason to do so (I feel sorry for Perl, because Larry Wall seems like a cool guy, but perhaps it's a testament to its influence on other languages that it no longer has uniquely redeeming features). I even read books on various applications. Naively, at the time, I looked at learning as a pure, unalloyed good — rather than a dangerous spend of lifetime I'll never get back.
I deeply regret wasting that time on that instead of learning a meaningful skill.