what's with korea and copying??

i got this question after watching a few kdramas in the past few months. I watched 4 (my goblin, queen of tears, lovely runner to name a few) and they all have these common plots where the ml gets into life or death towards the end of the season or there is some type of danger harming the couple. (some of the mls legit say the same ass lines) And i found this is not only in kdrama but in manhwa too eg yuri with red/pink hair horny antagonist, black hair fl and usually brunette protag or even in isekai romance with the cold northern dukes, ltr all mls being black haired, etc etc i just want to know ur opinions and why you think this might be the case