I accept that people who carry themselves like Rio did throughout exist, and therefore accept the character's portrayal in this drama, but I don't like that type of person (jaded but not funny about it, just really cold and haughty - we get it you're wounded. You're missing out on all the funny pain can make you).
Kido was an entire character. He is painfully, thoroughly riddled with his defining flaw. It's a juicy role and the actor made sure we had a lot to bite into.
It tangentially makes you think about the way you navigate the world, but I wouldn't say it's life-changing or inevitably perspective-shifting, though I can see some people feeling very confronted by this piece and maybe growing from the exposure! Good for you if so!
The story doesn't really moralize at you; you might grow in one way or another and no direction is really depicted as correct - every virtue is excruciatingly entwined with its paired vice.

It was fun to watch, but it made me think a bit, and I only like thinking three (3) times in one day so I can't say I'll re-watch anytime soon. I wouldn't say it's cerebral, but it's thoughtful: you get no answers so you walk away still grappling with the questions posed.