Sweet Teeth - more than 1 couple, all happy endings, with endings similar to what you wished. Though no action here,
Stealth Walker - lots of action and complicated stories here. Great romance too but it only really focuses on one couple. happy ending , enemies to lovers troop
Tienstin Mystic - action packed, multiple couples? but romance is not truly the main plot. At least not in season 1. there is a 2nd season where there is more focus on the romance. Its well done though . It also does not truly fall into enemies to lovers, more like bickering couples to romance
Dating in the Kitchen - one of my most favorite romance c-dramas. Seriously it is hilarious and amazing even when he first 2 episodes might seem a bit ridiculous. But the couple is golden, the romance moments are swoon worthy and the overall story very entertaining. No action though. Just romance and it only truly focuses on 1 couple. happy ending (enemies to lovers troop included)
Find Yourself - great story, lots of romantic scenes, more than one couple. happy ending. But no action here. just overall romance and drama. noooot per say enemies to lovers but they are at first not tooo happy with one another.
Go Go Squid - super super fun and cute story. Definitely an enemies to lovers troop. multiple couples too but main focus is on the main couple. Happy ending