"Maybe Do-hyeon is trying to make someone the next "heir" so he can just leave the company and ditch Jinah in turn leaving Jinah sad cause he actually did catch feelings for Do-hyeon in the process and Do-hyeon was never really serious about the relationship. Jinah thinks he's playing Do-hyeon, but its actually Do-hyeon playing everyone else. That's probably why he got in trouble last time cause he tried it once and he ended up getting snitched on making him look bad. Now he's trying again".
Then after Do-hyeon succeeded on leaving the company he will still feel something is missing ╮(￣▽￣)╭
To the five people who downvoted my comment about my theory last time that turns out to be right (^ _^)凸 Ayyyy.