Responses
I'm the reader and as a reader, I can express satisfaction or dissatisfaction with the progress of a romance.
Dan doesn't exist. He can't choose to love or not love Jaekyung. The author is puppeteering him to take whatever decision she wants him to make.
As such, as a reader, you absolutely can be critical of the progression of a romance irrespective of whether it bothers the characters in the dynamic or not

I’m proud of Jaekhyung for trying to make amends for his past actions bUT that scene reminding me what he did with the present Kim Dan got him for his birthday has me lying in my bed with my teeth gritted and fists clenched