Smart speaker using old Android box

I have an old Android box (4.4 and not upgrade-able) that I am thinking to use to create a wireless speaker (at least to play media and notifications) and maybe if possible even use the microphone for voice commands.
I looked at Android TV automation which might help with the first part which is music playing and notification using ADB
Another option might be to remove Android from the box and run Linux with some sort of media server ?
Any ideas ?