I use mibox for whatsl it is made for.. media consumption.. streaming. If i need something off Google drive i use file Managers drive integration and get the file i need usually an apk otherwise no other use. I find this is easier and faster than using any other side load options.
It's not supported by Google as an app developed for TVs.
But you can still try to sideload those, you'll probably need a mouse to navigate.
What's your use case ?