I will second this. I believe that if you were to live in Japan with a very solid hold of N5, 4, and 3 (including being able to output it without prompting), you would be very fluent. Though, generally I would say that focusing on N levels for studying order might be best for people looking for a certification that will help them for entrance into school or for job hunting. Using textbooks may start you out in the N5, N4 range, but you will definitely also encounter some N3, N2 stuff along the way, even before you are ready for N2. But that’s only natural.
I think following a study plan that is more comprehensive (fostering the four disciplines of writing, reading, listening, and speaking) will make you the most well-rounded in Japanese (writing may be not as prevalent due to the increase of typing - though it does help cement knowledge and tell the difference between similar kanji, and learn stroke order for some Japanese dictionaries). And as iterated multiple times throughout multiple posts on the Bunpro community, Bunpro is probably best used as a supporting member of your study-buddy-action-plan, and not your main source of language learning.
I have also met people who have passed N1 and can’t speak Japanese, though this may matter less to people who are only hoping for passive-proficiency (listening and reading based), and do not necessarily need/want to be actively proficient (writing, speaking).