Conclusion
No two people learn exactly the same way, so ultimately, you should learn however is best for you. But I do believe that, with all of the resources available these days, especially for free, the barrier to learning Japanese (and any language, for that matter) is lower than ever, as knowledge has become increasingly democratized.
The most critical concept in learning is simply: consistency. Even if you don’t follow this guide perfectly, or stumble along the way, as long as you keep pushing forward and move at a decent pace, that drive to keep going will lead to results at the end of the day. You will feel frustrated and discouraged at times, it happens to every new language learner, and to me on more occasions than I can count. So while it may be tough, hang in there, and just remember – if it were easy, everyone would do it!
頑張って！