I am just watching scent of a woman and the second female lead Im Sekyung she tries so many different ways to get rid of the female lead and just when you think she has accepted defeat she comes back for the next round. She is vindictive in her actions.

The one I'll categorically call need bigger boats to one-up each other is Monster(2016). I can't count how many time both the protagonists and antagonists rise, and fell. It was almost to no end. They needed the bigger boats the most.

Another is a C-drama, The War Princess Li Wei Young. These one had her opponents needing bigger boats. And even when they clipped her wings, their insecurities made them(the opponents) look for boats, again. In a position of grass and despair, or that of grace, Weiyoung had her opponents and those who mad her an opponent on thier toes.

Oh Yoon Hee in Penthouse is another gem - The one person who can legit make Joo Dante and Cheon Seo-jin worry about thier necks.
If I sat through season 2& 8 episodes of 3, it was because of Oh Yoon Hee.

Honorable Mentions
Bossam: Steal the Fate - Princess Yi Su-kyung.
Kang Yi Kyung in Glass Mask
Artificial City - Yoon Jae-hae.

Definitely Vincenzo. That scene where he has his first confrontation with the thugs hired to harass the people in the building and he ends up dangling their leader from a balcony? Yeah I'm pretty sure they needed a bigger boat.

I also think Man-wol from Hotel Del Luna was a bit like this. She was incredibly powerful, so when she pulled out all the stops, ghosts and humans often realized pretty quickly that they were out of their depth. And she looked completely fabulous while doing it.

Another would be the three female leads from Search WWW. None of them are lawyers, but they are all confident women in strong careers who make formidable opponents for each other and others around them. I think Se-ri from Crash Landing on you also falls nicely into this category.

There are plenty of others who are lawyers and agents and things, but these a few that I thought of. (Well, I guess Vincenzo is a lawyer, but not in Korea, so I'm not counting it haha!)

Watching Money Flower is like swimming in shark-infested waters.

Lee Sang-yeob from While You Were Sleeping.

Definitely the lawyers from Vincenzo

The Prosecutor from the show Sketch

The Father & Big brother from Untouchable

Lead pair of Hyena. They both typically went after each other so blood bath was often contained but if they worked together they could even take down the whale.

*ahem* in the Spirit of Cham Cham Cham, I object to this animalistic metaphor; sharks are gravely misunderstood and demonised creatures (thank you, Jaws, not) and I feel obligated to defend them against their reputation.
They're quite cool, funky guys if you just get to know them! Promise.

Anyway.
Baek Seung Soo, Hot Stove League.

The queen in Kingdom
Most prime ministers in sageuks
Mother in Arang and the magistrate

Q: Why do sharks not attack lawyers?
A: Professional courtesy.
Ba-dum-dum. 😆👩🏻‍💼⚖️🦈🥁

I think both antagonist and protagonist of "MY life again"
The lead was given that bigger boat 🚢

The veil. I thought our heros are a small group and needed more help
L.U.C.A:The beginning. I thought the organization is too big and to stop them we need equally strong power. In the end, their power just transformed to another organization
The silent sea: Existance of the lead girl and two astronaut wasn't definitely enough to stop researching on ...
38 Task force: To avoid going to prison definitely a big bady was needed.Of we had it, we could even change the ending although it wasn't totally bad
athena: No need to explain I think
Bridal Mask: I hope we had bigger organization on our side
The smile has left your eyes: 👀If ee had more power on our side we could have a happy ending
Duel:I hated the twin's lonliness and lack of power
D.P :A high ranking official👩‍✈️👮 could sort this mess ... I mean it was horrible.
Hellbound : Humans 🙍 were completely helpless
Squid 🐙 game:I thought a single police officer couldn't do anything

Hmm... @DaebakGrits opening comment made me think of Jo Yi SEO from Itaewon Class. She's an absolute shark! I really like how consistent her character is. She likes who she likes, hates who she hates, and does what she says. I respect her for that.

Another character that came to mind is Park Hae Jin in Cheese in the Trap. Love him or hate him, he's good at manipulation, fantastic even.

Finally character on my mind is Jung Geum Ja from Hyena. Oh she's good