Character progression of rich male mc and poor female lead, I know, but the Character Progression

So, Im looking for the typical setup of the rich male mc, who ends up romantically with a poor/lower status female lead, however

1) I would like it if the male lead had the "only child" sort of feel going on.  Really spoiled, kind of out-of-touch with the normal people (being an only child of a rich family or soemthing), but NOT a bad person.  Not evil, not rotten, not a d*$#, just....spoiled, maybe a bit arrogant.  I hope you can understand what I mean, he doesnt have to actually be an only child, just have that like, super spoiled vibe

2) For the Character progression part, I would like it if the male mc basically changes himself completely after falling for the much nicer, kinder, etc Female Lead, like, hard 180 from what he was before.

3) I would prefer if the male mc basically fell in love at first sight or something, like quick, and subsequently realized he needed to change to be able to woo her or whatnot.

Point 3 is negligible, and not really necessary.  Points 1 and 2 are mandatory, Im not interested in the rich arrogant douche who keeps on being a rich arrogant douche, or the rich arrogant douche who just becomes a rich slightly-less arrogant douche.

Though I suppose the opposite way around could work too.   Like, a really cool, nice rich male mc and an arrogant, douche female mc who does a 180 and becomes pretty cool to woo the guy is fine too.   Its that dynamic I want, so the other specifics aren't too important (whose rich, who does the 180, etc)

Shopping King Louis

I'll second Coffee Prince and 1% of Something. I'll add:

• Love in the Moonlight- rather than changing once, the ML goes through a couple phases pretty quickly 1) arrogant, vain, seemingly useless prince in disguise when he meets the FL (dressed as a boy) 2) arrogant, petty, playful prince enjoying teasing the FL 3) realizing they're friends, worrying about the FL, softening up towards her and protecting her 4) realizing he's fallen for the FL - he prioritizes and cherishes her and also takes his role more seriously / gains new political goals inspired in part by her commoner status. That last one might even be multiple changes. Even if some of his initial personality is an act, he still changes pretty drastically and quite quickly.
• Ms. Perfect - the ML is sort of well off (he's an attorney), but he's the type that wears knock-offs and relies on sugar noonas to provide him with nice things. He's superficial, handsome, and knows he's good looking. At first he admires the FL's work ethic (she's a legal assistant / working mum) but doesn't show it, he just works her extra hard. Before he even realizes he's started to like her, he goes out of his way to help her secretly. Very quickly he becomes a selfless, always-there-for-her rock that she can lean on when everything else is falling apart. I'm not a fan of the genre (mystery / thriller almost verging on horror) and there wasn't as big of a focus on the romance as I would've liked, but I stuck it out because really loved this pair. 
• My Secret Romance - the ML is a rich, arrogant, handsome playboy and completely spoiled heir (but not cruel or a completely horrible person). He meets the FL when he's forced to work incognito at his father's hotel. They clash at first, but quickly bond over their mutual unhappiness. They have a one night stand that neither of them can forget, but the FL runs the next morning and they don't see each other again until three years later when the FL unknowingly takes a job as the ML's nutritionist. He's changed his playboy ways because he couldn't forget her, and when she shows up again and pretends not to remember him he first focuses on getting her to admit that she remembers, but then focuses on wooing her. He doesn't have eyes for anyone else. 
• School 2017 - the FL comes from a poor family (they're paying off a debt). The ML is the only child of the school's director. They are well off and gets favourable treatment at school because of his father's position. He doesn't care about school and acts arrogant and aloof but really is closed off due to a traumatic incident that alienated him from his friend and caused him to resent his father. The FL discovers that he is actually the school vigilante (a role he partly took on to vent his resentment of his father, but which she mostly sees as a hero of the students), and they become friends in part because of the shared secret. He falls for her first, and largely because of her he opens up again, starts caring about his life and other people again, reconciles with his old friend and makes new ones, and even reconciles with his father. He's supportive, protective, and sweet towards her. 
• The Eternal Love - the 8th Prince / ML is a somewhat cold and calculating person (although not cruel / bad - he wants to be named crown prince to prevent his less intelligent, morally questionable, and power-hungry brother from taking power) and he's pretty indifferent to the women around him. When he first meets the FL (it's a bit complicated, but she's part real estate agent part noble daughter of a concubine, so there's a class difference) he's the same towards her and suspects that she is spying on him for his brother (and in a way he's sort of right), but her unique personality piques his interest, and his suspicions quickly become playful. Moments where he's protective towards her go from play-acting to real. After a fairly short amount of time he decides to let go of his suspicions and trust her completely. He has eyes only for her, dotes on her, and puts her well-being before everything else - including power. 

And perhaps:

• Hi! School - Love On - the ML is an only child (sort of), he's talented, good looking, and knows it. He's a bit full of himself and a little bit arrogant towards the girls that like him (although he's still the type of person that will risk his life to stop one of them from jumping off the school roof), but then he meets the FL and treats her very differently (as the lost duckling who saved his life but lost her memory and needs looking after at first, and then he falls for her). It not so much that his whole personality does a 180, but he definitely treats the FL differently from other girls - he's more comfortable with her / opens up to her and shows his sweetest side with her. He's not rich, but he / his grandmother own their apartment above their store, while the FL is a penniless angel-turned-human so she relies on him. 

Maybe City Hall? 

https://mydramalist.com/251-city-hall