Terence Tao has well over 50K citations. Maybe one can argue that he’s gaming the system because he alone can decide what problems are deemed to be interesting by the broader community, but he can’t help that.
Yes you can get a 7/7 score for a combinatorics problem in IMO with a good amount of handwaving e.g. instead of formally describing a configuration of monsters in P5 of IMO 2024 you can get away with a few sentences that describes what you're doing. There's actually a decent amount of compression being done by using informal language, so I expect formal proofs of combinatorics problems to be significantly longer than formal proofs of algebra/number theory/geometry problems.
I should say that handwaving is also ok in other topics, but formalizing handwaving in other topics is easier.