I think using a PC in this manner is overkill/overly complicated for a modern AVR and/or a modern streaming device!
Example--Denon HEOS works great! My Denons (AVR4400, AVR3300) are on my home network (1 is hard wired, 1 is Wifi), and I have 256Gb SD card in my phone. So, I can simply choose the AVR with my HEOS app, start a playlist, and BAM! audio is on my Denon over WiFi, no PC needed!
If you really want/need a local device, I would be inclined to look to a Raspberry Pi solution, rather than a full-blown PC! RPI is not plug and play, but tutorials are readily available and there are plenty of advantages to that option.