I asked “RetroRGB Bob” which bluetooth solution he adviced for my MiSTer setup and he told the Rii X8 Mini is nice as it’s has it own USB receiver which works very good. It’s indeed very responsive and being able to use it without any hassle, it just works.
The good part is you can use the touchpad as mouse and the keyboard for entering some input. It’s not for writing an essay but it’s nice to type on IMHO.
Information:
http://www.riitek.com/product/x8.html