I hope I'm not the only one who experienced this.
I use a USB to Ethernet adapter/hub to hard wire my Mi box to my network so it's a more stable connection and better performance.
But it seems to get worse performance than wireless at 2.4 or 5 ghz.
I have a USB drive connected to my router and I noticed that with the ethernet adapter, whatever video I'm watching on my Mi Box (through Kodi), the video would eventually freeze up. Disconnecting the ethernet adapter and going on 5ghz wireless solves the issue. No freeze ups when playing a video from a USB drive on my router.
I thought a wired connection would be faster/more stable than wireless?
I have a similar set up with Mi box 3 with the ugreen ethernet hub- no issues like you're having but I don't use Kodi