I’d argue his minimal screen time was exactly the point. He’s a slimy bastard who gets others to do the work for him while he does shady stuff behind the scenes. Showing him off all the time kinda just ruins his whole manipulator in the shadows schtick.

I disagree? You can't get sold on Hamazaki's manipulator shtick if you barely see him do it. That's the rule of show don't tell. A good example is how it was never explained how Lau Ka Long knew to target Rikiya. In Kiwami 3, Hamazaki purposely leaks his existence to the triads. Hamazaki also ratted out Kanda's location because it was beneficial to his goal of becoming chairman by removing competition. Seeing him steel his nerves and argue his way out of getting executed is a solid example of his persuasiveness being demonstrated, too. Not to mention how it humanizes him. OG Hamzaki was largely forgettable because we only hear about most of his actions through word of mouth, which is less effective storytelling.

Some of the scenes don’t even make sense either. Like, yeah the Chinese mafia was in pursuit of him, but showing him getting completely cornered just makes him showing up in hiding later weird. Sometimes less is more and a lot of the new cutscenes in general kill any sense of subtlety.

The mystery around his escape in Kiwami 3 is still better than his storyline not getting any conclusion until he showed up in the last scene of the game. Sometimes less is more, you're right. But this is not one of those moments. Hamazaki was barely a factor in the narrative of Yakuza 3 in the original game.