I cannot see them getting together now that Do-hyeok went after his family and their business. Do-hyeok just keeps upping his assholery lmao.
For now, I can't see him having character development 'yet' even after 'all' he went through. Until he even 'considers' getting therapy, he'll probably just keep fucking shit up and continue being a jerk in these side stories.
The ending of these sides might be him completely losing Siwoo and all his chances with him and it will be JUST THEN that Dohyeok's life-changing jerk-ending character development will really start. And we see him contemplate everything that happened lol. Siwoo might just be his 'the one who got away' that made him realize he needs to be a better creature.
Idk tho. Dh's such a bigass jerk. I HONESTLY would be more surprised if they somehow DO end up together than not.