
Well it's not for everyone and each their own, so I won't try to convince anyone to enjoy something out of their taste, as you shouldn't neither drag others preferences.
I get your perspective and view of it, so I'll just say quit it or give the novels a try. But there's not point in keep reading something that you're not enjoying.
The thing with this story is the novel's length. Unfortunately the first part, is pretty much as you "described" and it's the only officially illustrated one. But put in perspective, this webtoon ain't even a third of the whole plot.
The whole story is pretty long, there's like 5 or 6 novels, and even though the first part is pretty twisted, once that one is done, the story takes a progressive change, and so do their characters.
I do find how Ilay changes and tries, interesting and cute, how their relationship develops slowly cooked too. They have a pretty unique dynamic relationship, nothing too cheesy, but pretty meaningful in the simplicity of their conversations and gestures, once you see the progression of it.
I don't want to spoiler neither try to convince you, because honestly, the abusive bullshit the author tends to write sometimes is overwhelming and disgusting. I'm finding myself struggling HARD to finish the novel part I am in, with Christopher character rn.
But whatever, just wanted to share a bit of my own insight of this whole story.

Honestly, to each their own, but I do believe Ilay is more humane to Taeui than Ceasar to Leewon. Both raped their partners at some points so both are black af. But, Ilay has been avoiding hurting Taeui throughout the manhwa in terms of physical violence like punching to death/ shooting / etc. This manhwa is a mega slowburn, the 2 characters take a long time to fall in love and REALIZE they fall in love (especially Ilay)
I fall in love with Ilay x Taeui because of the later sequel novels. I wasn't that crazy about Passion manhwa before reading the whole entire series (cute spoilers here and there made me hunt down the entire series to read). As Piti said above, up to now is only ~ 1/3 of the novel series. To be specific, Passion novel ( 6 volumes, we're at Volume 5 right now) is about them meeting and slowly falling for each other. That's it. You only see their relationship dynamics / how much they love each other in the sequel series of Diaphonic Symphonia (5 volumes) & Suite (5 volumes). Very longggg way to go.....
Back to Passion, Taeui is the only person who treats Ilay as a human. Despite knowing Ilay's cruelty and craziness, Taeui tried to save Ilay multiple times and took care of Ilay when he got attacked etc etc. Ilay slowly fall for Taeui but Ilay didn't believe he's capable of such thing that's why he has been acting like a contradicting idiot. He acts as usual but cannot act like usual at the same time because he really doesn't want to be hated by Taeui. When Taeui left, Ilay was depressed and went crazy because he thought Taeui really hates him afterall. I LOVE how Taeui is his only exeption. Even Taeui knows Ilay treats him differently but doesn't want to admit and under the same mindset "Ilay is not capable of loving another person". Imagine the cruel, handsome, strong guy gives you special treatments but not anyone else. That's the trope lmao. Their actions/behaviors subsequently affect each other and lead them to love :) They are both in hardcore denial right now. At this point, Taeui has realized that Ilay has feeling for him & he also develops feeling for Ilay who is a fking psychopath so he still tries so hard to deny everything. On the other hand, Ilay doesn't even understand that he's in love so.... that's that ... The love is there so clearly. Ilay is acting contradicting left and right because he still doesn't understand his own feeling....

Spoilerssssss warning (Chris x Richard)
@Piti - I hated Richard, he was terrible and cruel to Chris in Diasym. Poor Chris. Seriously fk Richard arggggggggg!!!!! I literally only adored Ilay x Taeui sweet moments in Diasym but those were much rarer However, if you read Suite side of Diaphonic Symphonia, Richard did acknowledge his wrongdoings in Diasym and tried his best to show his love to Chris. It took a few years so yeah..... Idk how far you are with the novel series & I don't want to spoil too much Their love story is very unique, it starts making sense to me eventually .....but tbh Richard is still not a very likable character to me Private message me if you want a friend to discuss about Passion ~

@Sun - The translator warned people not to spread the website because it's illegal fan translation at the end of the day. Their translation is very good though, so I really want the website to stay online for a long time (so I can re-read the series whenever I want ).
Don't be offended but I'm re-reading your original comment about Passion, so I'm quite unsure if you will turn around ....? The novel series are long af, and author-nim loves to starve readers, only sprinkles sweet moments of Ilay x Taeui here and there
This was the absolute worse manhwa I ever read. I don't get the hype, if anyone can try And explain to me how could this Story And their "relationship" be considered anything but disgusting horryfying trash full of rape And emotional And physical abuse I would like to hear it because I really feel like throwing up rn after rading this