It's a fairly new project with missing features still. No hardware video decoding is the big one, causing performance to suffer greatly at the hands of a low-power TV CPU. The
latest demo I saw was skipping frames at a 720p30 target. Moonlight/Game Stream can definitely do 4k60 right now on a streaming device that's capable of it. And you'll probably want wired networking too (a USB 3.0 Gigabit adapter should be enough on the Xiaomi even though capped by USB 2.0).
You don't need Moonlight software on the host PC. The Moonlight client (i.e. the device connected to the TV) appears as a Shield device to GeForce Experience, whereupon GFE will want to pair it. The games are managed entirely through GFE. GFE should automatically add officially supported games on your PC, and other games can be added manually. Once added, they will automatically be picked up by the Moonlight client over the network. If you have a lot of Steam games, you can just add Steam itself and stream Big Picture Mode better than Steam Link does. You can even add mstsc.exe and stream your desktop.