Seems like you and me are in the same boat. I usually become disinterested in a lot of dramas when I try to watch something of the same plot continuously. Maybe try switching up the genres? Looking at your list you really like the Romance Genre and Youth sort of genres. Let me give you some recommendations of alternativs and see if that helps!
I'm Not entirely sure if you are into action and stuff like that, but let me recommend a few that are completely opposite to watch you typically watch!
Duel - This is a Sci-Fi action! It's a full on action and something interesting happens every episode. There are no strong love lines in it however, unless you count the fathers love towards his daughter!
The K2 - I saw that you watched healer and rated it 10/10. This one has the same actor and I find it to be similar to healer but better. It's a good action drama with romance and schemes all throughout it.
He is Psychometric - I saw this on your list and I definitely recommend it. It is a romance and not as action packed. But it gets better towards the end of the drama. Unlike the other two above, it is a slower moving drama.
Introverted Boss - Since you are into Romance, maybe try this romantic comedy? This is one of my all time favourite romcoms. Try and get through the first couple of episodes and then it gets better!
Also with An Angels Last Mission: LOVE. The drama moves depressingly slow in the beginning. I struggled watching it too since it's not my usual genre of drama. But the ending is a lot better, so when you feel like it, definitely try watching the end!
