It's pretty simple, his story was actually the author's first story, but she released it much later. So it has nothing to do with deserving, the author made that character like this intentionally. And it was actually the most anticipated story of the author for years, and was one of the most popular stories on the platform it was released on last year, even won a price there.
What you and others probably don't know is that KMIYC is actually several years old. And some of those characters were already in Kiss me liar before. As a manhwa only reader of KMIYC you lack a lot of informations. You have no idea who Grayson's pair is going to be if you didn't read KML. Although he should appear in one of the next chapters of KMIYC, but Grayson's story takes place a few years later.
Most didn't start reading it because they were rooting for Grayson ( i think very few started reading it because of that ), no, it was because he had to deal with Dane Striker, who was a fan favorite of KML, who on top is a dominant omega.
They are not whitewashing the shit Grayson did, since Josh is there too, because he and Dane are friends. Ashley also warned Dane, and told him some of the worst things his son did.
And Bliss, Bliss is the most pampered/spoiled and loved family member (you will feel even more sorry for Chase when you read that, at least I did). He even asks Grayson for advice lol. But the father is extremly paranoid. And that is not from Grayson's story, that's from Bliss's.

bro i started reading this march 30th and it came back MARCH 31ST?!?? IM SO LUCKY OMFG BUT I HOPE THE BROTHER FUCKING DIES FOR WHAT HE DID TO CHACE UGLY PIECE OF SHIT DICHEAD BITCH