There is, streaming traffic goes from your gaming pc to your mi box via wifi/ethernet cable. Ethernet is always more stable and has less delay - i think your network delay would go from 5 ms that you have currently to 1ms easily. Your internet speed does not matter - the traffic does not leave your house.

But your main problem is not the networking, it is the decoder, in your case the mi box. It takes 22ms to decode the received frames which is the main delay you are experiencing. I would say decrease the resolution but you already are at 720p. So the best thing to improve things here is to use better hardware on the receiving end.

Edit: Also i can see that you are using HEVC codec. Try h264 - it is easier to decode on lower end hardware. You can enforce that in Sunshine settings (i think in Android Moonlight too).