Kill Lover

Both dramas are about the leads seeking revenge against one of their fathers, with the two entering a enemies to partners in crime to lovers relationship. Both MLs are mysterious figures with morally grey actions but a good heart. Both have a lead talented in the arts (music vs. painting) and involved in business. Both dramas have a similar vibe and good chemistry between the leads.

Both ML has a similar vibe, the relationship dinamics is really similar.
Plot is a little bit different here.

Both FLs return after being presumed dead to take revenge and/or reclaim what was theirs, teaming up with the son of the family they're fighting against.

different in terms of plot but similar in terms of chemistry between leads and the mysterious and handsome MLs

Both have similar vibes and intros, both MLs are seemingly unpredictable and calculating with a hidden plan. Both FLs pose as someone close to them (fiancée vs. sister) to enter the family household. Both couples start off antagonistic, and have a lot of chemistry from the beginning.

Both has revenge plot and some action.
FLs approach MLs with motive/ purpose.
In both series FL and ML team up somewhere
In both series MLs first seem bad but actually they are not.