If what you mean by peak comedy is lots of belly laughs as well as great, snappy dialogue and a fast pace, then here are six extremely laugh inducing romcoms. And my top pick for you is vintage:
My Lovely Sam Soon (2005) - Like Business Proposal, there's an obnoxious boss, a resilient Cinderella, and cooking. Sam Soon is an indomitable spitfire of a baker who always claps back. She's feistier than Ha Ri of Business Proposal, but they're both determined and strong. Restaurant owner Jin Heon puts out a level of insufferable that matches Business Proposal's Tae Mu. Watching a 2005 drama is visually taxing at first, but then the awesome writing takes over and rewatching it is more satisfying than most of what I've watched from the 2020s.
Marriage Not Dating (2014) - Hilarious love hexagon (six characters, mix and match) with fake relationship, forced living together, messy love triangles, lots of great laughs and slapstick humor. It also has some depth. The drama visits a couple of parental train wreck marriages, and treats them with humanity and humor. It's a 2014 drama, and I see the oldest drama on any of your lists is Weightlifting Fairy (2016), but Marriage Not Dating is a hoot and a half. I laughed harder than I laughed at Business Proposal. The additional four episodes pay off in more character development and complications to drive the humor. In contrast to BP, she's not his employee. He's a cold plastic surgeon, and she's figuring out what to do with her life, so there's some status difference there.
Don't Dare to Dream (2016) - ML Lee Hwa Shin is hands down the meanest ML I've ever come across in a romantic comedy, and far outdoes Tae Mu when it comes to tormenting FL Pyo Na Ri. Ah, how satisfying is his fall! This is a great, sharp romcom about backstabbing and workplace competitiveness, and eventually about the human connection and social ties that underlie the superficial veneer of professional conflict.
Bromance (2015) - If you're up for the level of silly of BP, then you have to stretch a bit more to take on Bromance, a lafftastic celebration of swoon. It's first on my list of Happy Place Romcoms. Please see the list for the reco for this one. It's very different from BP in terms of plot and tone, but it's peak comedy, just of the cuteness overload variety. In contrast to BP, this particular boss is an utter sweetie pie.
Speaking of the above list, the other super funny romcoms I vouch for on the list as comparable to the high energy, wacky, upbeat BP are Cunning Single Lady (2014, super tropey, but super ROTFL) and The Greatest Love (2011, after the first episode, I'm laughing too hard to care that it's a little dated.) Both have the higher status, initially cold ML.
