I can't understand people's gripe with this plot...but then, to each it's own. I genuinely find this plot riveting, and I've been following the story since its fan translation days in 2020. 3 years on, I still can't put it down, and I'm usually one that can't tolerate bad plots.
I particularly love Mujin's and Cho Ah's dynamics. They are clearly in love and we see their relationship growing just like any couple. They clearly love each other but with the weight of Mujin's big secret bearing down on the relatioonship, it's inevitable that there will be drama - which I love. I'd say do yourself a favour and stop reading the story if you hate it that much - honestly.