Something in The Rain (the Korean to English title is funny - Pretty Noona Who Buys Me Food) - a slow burn noona romance with two storylines. One where she and her fellow female colleagues suffering inappropriate sexual advances at work dinners and how her desire to keep her boyfriend from worrying is part of the reason why she is taking a stand. The second, is obviously the reverse age gap between her and her boyfriend (who at one point, knows she is in danger and rescues her). Throw in a crazy ex-boyfriend, a very snobby, class focused mother (seriously annoying lady - makes the mother in Jane Austen's Pride and Prejudice look positively lovely) and you have a pretty solid drama. I binge watched it and have re-watched it many times. The ending for me was a little disappointing as I always want to know what happens after.
Doctor John - I forget why but she almost quits being a doctor during her residency years, meets him and they work together to help people in the newly set up pain clinic. He comes to her rescue (so to speak) during a suspected infectious disease lockdown and she saves him a few times too (I do like FLs saving MLs as well).
It's Okay to Not Be Okay - her mum is a psychopath (for want of a better term) and tried to raise her as such. She is now a children's book author and she often has REALLY scary dreams. He is a carer in the mental health field as well as for his autistic (?) brother. All three end up saving each other. Love the FL's clothes.
Love me if You Dare - cdrama. Had to throw in this one even though it is out of China and you were asking for Korean ones. I don't know if she has PTSD but she did have a nasty experience in childhood that affects her into her adulthood. It is a profiler/cop drama plus romance. LOTS of interesting single episode storylines and a very long overarching story line with some seriously scary dudes in it. The ML definitely saves her in a clever, full-on way.