The Chinese community has a giant infrastructure of apps they use to get programming. You can easily resell it and get you can probably get most of your money back. Don't delete anything, as it may already be set up for Chinese TV.

Bought 2nd hand from a chinese guy. Got a chinese product. I don't see the problem here.

What operating system is it using?

There is no way you can install AndroidTV OS on a chinese Xiaomi box version.

Btw there is a guide and custom firmware for that chinese box on xda-developers forum

Check also atvxperience they have an AndroidTV like OS for the box.

Good luck