Only kdramas, maybe jdramas (only if they're are a perfect match for what I'm looking for)

1) Romance as the main and pretty much only focus of the drama

2) ML falls in love first (A MUST!!!!!) - he's overprotective, jealous and all that stuff, NO hate to love relationships  pls 

3) HAPPY ENDING - they simply end up together and i don't mean ending together like in[spoiler] crash landing on you[/spoiler]

4) If one of the leads has some kind of dark past, weird condition etc it HAS TO BE A FEMALE LEAD

• Weightlifting fairy Kim Bok Joo (romance/ML falls in love first/happy ending/no dark past, there's a bit of sport 'cause they're in a sport college but romance is the main focus)

• Coffee prince (romance is the main focus and it's also a very intriguing story/not sure if the ML falls in love first but he's the first to make a move and confess his love/happy ending/no dark past)

• Strong woman Do Bong Soon (romance main focus but there's a bit of fantasy and mystery/ML falls in love first/happy ending/no dark past)

• Reply 1997 (romance, friendship & school/ ML falls in love first/happy ending/no dark past)

• School 2017 (like Reply 1997)

Idk if you've seen it but Because This is My First Life is a fantastic romance. I don't remember if he falls in love first (I think they fall in love at the same time??) but he does get overprotective and jealous really quick. It's always my first recommendation.

Dramas I'm pretty sure fit what you're looking for but it's been a hot minute since I've seen them:

• I agree with What's Wrong with Secretary Kim!
• Flower Boy Next Door
• Fight For My Way
• Pinocchio (the ML is the one with the dark past tho, however the FL has a condition)
• Doctors (she had a crush on him in high school, but as adults I'm pretty sure he fell first)

Others:

• Introverted Boss - ik you said no hate-to-love, but this is kinda tricky because while it started with hate to love on the girl's part, the viewers complained and the writers quickly changed the plot so she realizes early on that the reason she didn't like him was a misunderstanding. He most definitely falls for her first tho.
• You said korean and japanese, but the 2004 taiwanese drama MARS fits like all of that. It's older so it's a bit more chill, but it's a passionate romance if you're in the mood for one.
• Put Your Head On My Shoulder - it's a chinese college romance. he falls for her first, and there isn't really any melodrama. jealousy against an ex-boyfriend tho.

The male chases female first tag might be a big help to you too! https://kisskh.at/search?adv=titles&th=763&so=popular&or=desc