priince of waffle or whatever

I feel like these 2 quotes are literally the core of Kim's character. Like yeah he spills the whole thing here.

People don't become that reflexively defensive over harmless/positive things for no reason; they become defensive because they've learned to be prepared to be attacked.

Kim is very obviously a competent and conscientious detective who should be more senior in rank than he is, and who was stuck in a junior-level position that he found humiliating (being forced to go undercover as a teenager when he was a grown man) for much longer than he should have been, until he finally had such a large success (with the pinball case) that his precinct HAD to promote him.

It's fairly obvious from what you see of Kim that he deliberately buries everything about himself that could potentially present an avenue of ridicule or attack under a heavy layer of Being The Consummate Professional at all times. And part of what draws him to Harry so quickly - and makes him enjoy Harry's company so much - is that Harry, while on the surface the embodiment of the sort of toxic masculinity that Kim has been dealing with his whole career, actually has the two traits that are basically Kitsuragi Catnip:

He genuinely and openly admires and likes Kim, respects his skills, defers to him professionally, and praises him to others - and he is senior enough and has a good enough reputation even given his recent issues that Kim feels like that means something.

He does all the bonkers things that Kim secretly wishes he could do while being so over the top that Kim will ALWAYS look like The Sane One in comparison, thereby allowing Kim to let loose a little/ live vicariously, but SAFELY.