I wouldn't say this is the place.

If you are in Europe you are very likely viewing 25fps IPTV streams.

You want to match the Mi Box - Screen Resolution & video output Refresh rate to those streams.

Quit SPMC and then in Android System settings try > Display > Screen Resolution > 1080p50Hz

Then restart SPMC again.

Trouble is when you watch movies you will want to manually switch back to 1080p60Hz otherwise there will be bad judder.