I guess the image I have of Hjyj is that of a frail human holding a rather thin leash connected to a monster who willingly submits and never takes off that collar around his neck that the leash is attached to - it's a willing submission and a illusion of who is in power

YESS, exactly! For one, I do believe that his 'abuse' is also almost a coping reaction to Hyunje's 'perfection' and power (physical, financial, political) which inevitably triggers someone who is as deeply insecure as Yoojin is;

Well what if there is this old man who is so annoyingly perfect & powerful that not a single cell in your body makes you worry about them & the behavior you show them. So you just let all your selfish & greedy feelings out when he is around. What a new & fun feeling that must be!

I love when Hyunje is like ⌒‿⌒ when his partner is giving him special attention filled with love (calling him names/gaslighting him/exploiting him)

Everyone talking about slam dunk yaoi but I just have to call my hajime no ippo fujos out for being very dedicated and passionate as well (I'm dedicated & passionate)