Did something similar, and in my experience the vent probably won’t be enough. If I did it again, I think I’d do a watercooling solution, instead. I haven’t actually done watercooling myself yet, so verify first, but I see no reason you couldn’t route the tubes through the back and release the heat externally. The cooling could be attached to the back of the drawer, so that it all stays together. That’d also reduce the size of the holes since you’re trying to preserve the look of the desk more.