Wow, those last two chapters were good. The main character pushed this guy's psychological buttons in a remarkably plausible way, one that was set up by everything that happened to the guy in his own focus chapters.
This goes a long way towards redeeming the stuff that people have been seemingly-appropriately criticizing as being a huge pacing issue that gratuitously takes focus away from the story's main character and main conflict. The shit focusing on Choi Young-Joon was necessary to set this up: it makes it feel earned. A slow-burning, naturalistic 'show, don't tell' approach for characterizing a fighter who intelligently takes advantage of his opponent's weaknesses by actually displaying those weaknesses beforehand in detail, rather than the bullshit Sherlock Holmes approach where a character starts pulling details from their ass without the audience ever having had a chance to see any of it beforehand.
I was considering dropping this beforehand, but now? Not in a million fuckin' years. That was artful.