> Example, if you make over around $85,000 USD, you fall into the maximum tax bracket, which is 35%.

In the US, the maximum income bracket has a 39.6% marginal rate and is reached at $400,001 in AGI for a single filer; the (weirdly narrow) 35% bracket starts at $398,351.

So if Korea has a 35% top bracket, witha 10% surtax, that starts around $85,000 USD, I'm not seeing how that's "overall very light when compared to the States".