It's for 64-bit Android only. Most budget boxes on the market now are 64-bit CPU running 32-bit Android, which make them impossible to run Dolphin. Shield runs 64-bit Android TV.

https://dolphin-emu.org/blog/2018/08/14/state-of-android/

Unfortunately, Dolphin has not returned to the Android T.V. Store because Dolphin does not support 32-bit devices, and the review process seems incapable of understanding that Dolphin does not attempt to target 32-bit devices.

Fire TV 2 also runs 64-bit Android (Fire OS of course) but later generations switch back to 32-bit.

http://www.aftvnews.com/amazons-fire-tv-3-is-a-64-bit-device-running-a-32-bit-operating-system/

Probably not. But I can tell you, a Ryzen5 1600 and nVidia 750Ti will run Gamecube, Wii and WiiU games just fine.

Not even Shield runs Dolphin perfectly.