
Yes, the first two are like Kiss The Scumbag, more like standalone stories in the same universe.
Run Away If You Can (story of Nathaniel Miller, release was postponed to October), will be part of the " ...If You Can" series, stories about the Miller family.
"Kiss me, Liar! is actually part of the "Kiss Me..." series, Angel and his children from 5 different alphas, but the author only released that one so far.
I only know that, because the author released a list of titles she planned to write for those two series a few years ago.

Holy shit. Who are the couples in each on of those novels? And are they somehow related to Keith or Yeonwoo? I came here because I wasn't sure if I had to reread this godawful story to start on KMIYC. But wow, there are this many stories? Are they better than KML? Because I seriously hated reading this manhwa and I finished it because I thought Keith would become better but he honestly never did.
So how come no one mentioned there were so many related series in this universe! Huh. Come on. Tsk. So many don't have manhwa's too. UwU
Related Series
Kiss Me, Liar (Shared Universe)
Kiss Me if You Can (Shared Universe)
Desire Me If You Can (Shared Universe)
Eat Me Up If You Can (Shared Universe)
L*ck Me If You Can (Shared Universe)
Kiss the Scumbag ((Shared Universe)
Kiss The Stranger (Shared Universe)
Kiss My Grits (Shared Universe)
Run Away If You Can (Shared Universe)