So I'm thinking of adding Wifi to this build. While the mobo lacks wifi and there's no free expansion slots to add PCIE card, there is the mPCIE slot on the back of the board and the laptop I recycled had an Intel AC7620 adapter which is currently in a drawer anyway.
So something like this shouldn't be too hard to install, connect, and then feed through the case so that the antenna themselves are outside the metal case but underneath the plastic facade. And what kinda gloried Steam Box doesn't have wifi?