If you're wanting to build a separate Zigbee network, I would personally go this route (in-fact, I have).
This will let you use those inexpensive Xiaomi devices you were asking about. For $45 you can get a Conbee2 Zigbee dongle which works very well with those and many other Chinese devices. IKEA devices do particularly well with it too. The integration will bring them back into HE where you can use them with the far simpler to use automation and better stability. In other words, I use HA as nothing more than a device bridge.
As for the Hue, I keep mine on the Hue bridge. I have it already, it works well and the HE integration is really good.
