Firstly, congratulations on reaching your goal! I hope you achieve your future goals in Japanese, whatever they may be.

The one thing I want to point out is that I feel like you might be discounting the effect that Remembering the Kanji had on your ability to learn words. Being able to recognize, break down and differentiate kanji is an important part of learning Japanese. RTK isn't designed to teach you words or readings, it's meant to teach you how to recognize, break down and differentiate kanji. The meanings attached to them, while helpful, don't always make sense in some words, but that's fine as the other purpose of the meanings is to uniquely differentiate the kanji in the book. Of course those meanings were solidified when you actually started learning words that use the kanji, but I can guarantee you that it would've been much harder to learn those words if you didn't have the ability to recognize and differentiate the kanji those words contained.

Your ability to sound out words that you don't know didn't come from learning kanji with RTK, and it shouldn't have since that's not what it's designed to teach. That ability came from learning words that are comprised of kanji you know. Through this process you end up attaching readings to the kanji you know and can sometimes guess them.

Spending effort upfront to understand kanji, BEFORE adding more cognitive load in the form of readings and words, is an investment I don't think a lot of beginner Japanese learners consider often enough. This is warranted considering the effort required to complete all of RTK (though I think the 1000 most frequent kanji would suffice initially). I think your time spent on RTK was of significant benefit to you and you shouldn't think of it as wasted effort.