I was also thinking about using an external sound card like this for better audio:
The Sound Blaster X5 is an external USB DAC and amp sound card that is packed full with top-notch audio components, including 2 Cirrus Logic CS43198 DACs and a fully balanced Xamp headphone bi-amplifier. It supports playback of up to 32-bit / 384 kHz and DSD256 ultra-high resolution, and doubles...
au.creative.com
A well built PC is an excellent streamer. However you need to be able to build a purpose built computer. You need a 4K video capable board at least, that has an HDMI output. I am using an Asus board.
Make sure you use a top end power supply. I use an Aurum Gold.
Picture and sound are sperb and second to none. It gives just as good video and audio as anything else. You can connect to pretty much any stream that is out there.
I am on my third HTPC build now. When I upgraded to 4K my first board was not the best, but when I upgraded to this higher end Asus Republic of gamer board it has been probably the best quality source all the way round.
A well designed and built PC is about the best media player you can own, and far better than any hunt and peck app based streamer.
I built my first HTPC 13 years ago. My HTPC is probably my most used source component. I also have another purpose built computer in the rig, which is my Digital Audio workstation. I built my first DAW just 22 years ago, when that was really cutting edge.
My view is that no AV system is complete without an HTPC, as if you don't have one, you will not have access to a lot of content. Most of the content I watch is not accessible any other way.