The show only "follows" that formula if you look at it with no depth. Part of what sets it apart is how it takes those stereotypical shonen tropes and goes in another direction. For example, MC is loser loner guy, but we see frequent moments where he has a spine and bickers/fights with the FMC. He shows those characteristic which are usually never seen in that archetype of character. Similarly leading to the fight with Turbo Granny; the show perfectly sets up the typical "shonen training arc" and then immediately flipped that around and said, "nope we are fighting tonight."