I know it’s not what you’re hoping to do, but try mounting your motherboard and components on a decent piece of wood and hang it on the wall. No worries about trying to vent and cool a drawer, or cutting into a nice old Steelcase desk. I did this years ago, screwed everything onto plywood and hung it on the workshop wall. Looks kinda cool. Works just fine, can dust it off with the air compressor when needed. If you do mod the desk, good luck and hope it works well. I understand having an idea and really wanting to make it happen.