Replacing chromecast with mac mini questions.

I would like to change my chromecast to something else with more features (i could buy an apple tv or a nvidea shield) but i have some mac mini’s left what i can use. Best would be to make it so that i can use the mac with a siri remote but i would want it so that i don’t need a mouse to controll the mac but use the remote with mapped arrow keys to select elements of osx instead. Maybe use the launchpad with shortcuts for things like a netflix/disney/prime( trough safari) , but i’m not sure its possible to controll websites with arrow keys only. Other apps would be a picture viewer, spotify and probably steam link or moonshine/sunshine to play some games with bluetooth controlles on my gaming machine upstairs. Anyone some tips how to go about this? Edit: The possibilty to stream/aircast to the mac mini would be nice too