Even if the deal they made was struck, that length of his sentence reflects the severity of damage it cause and that gave officials to impose more harsher penalties.
Plea agreement can help him to reduce the length of his charges, but he might struggle to have this kind of settlement. I'm looking at possibilities if he have chance to get freed, but it seems that there's no immediate path towards getting his early freedom.
So Do Kwon would provably stay in prison for long time.