depends on what you need it to feed
you can run squeezebox on amazon fire sticks and fire TVs. I run it on a few devices here at the house.
The only downside is you dont have the interface so would have to choose tunes from a browser. I use either my phone or PC if im sitting at it
new fireTVs only do hdmi. the older oneds did both HDMI and optical. so you could probably find a refurb
I also use plex. Im pretty sure gapless playback is stil and issue with that though in case its a deal breaker, Plex runs on the fire stuff as well.
If you are running a NAS some of them have similar apps built in etc