Regarding the Open Source Streamer project thread, my take is that it's dormant because almost all the goals are now met by Moode. There are links to existing VU meter visualisation that could be used if anyone is sufficiently bothered. It's been confirmed that active crossovers can be configured through Moode's existing CamillaDSP interface, but suitable low cost DAC options are a sticking point, and the semiconductor shortages have hampered one contributor's attempt to fill that gap.
On the hardware front you can make it as off the shelf or as custom as you want. Audiophonics (among others) have kits that do everything but the trigger, and modules that you could use to add the trigger. Some have even been tested here. A bit of web searching should find you tutorials for diy streamers with no display, little OLED or LCD displays to show track details etc. or even the full 7" Pi touchscreen.
https://www.audiophonics.fr/en/network-audio-players-raspdac-c-6314.html
https://www.audiophonics.fr/en/network-audio-players-rasptouch-c-6350.html
https://www.audiophonics.fr/en/preamp-module/audiophonics-kit-diy-trigger-module-p-9318.html
Alright, thanks for mentioning this. Looking at Moode, I can probably use CamillaDSP for applying custom filters to correct for my room after taking measurements with REW. Which would be fantastic, as my Yamaha receiver nicely cleaned up some room modes where the sound signature is much flatter and cleaner now, and I'd love to add that for a dedicated network streamer. Do you happen to know if it also has some sort of dynamic EQ, where it'll boost low and high frequencies at lower volumes? Both Yamaha and Denon (through Audyssey) have such features, which again I find very useful as I don't often listen at reference levels.
That link to Audiophonics has given me an idea to try building it myself. Just need to find a good DAC eval board that's also affordable. I saw that Digikey has the AKD4499 DAC eval board, but at $1,190 a pop (at which point I should just buy a high-end off the shelf thing). Need to find something better. I guess I could also look at ESS, though looking at all of amir's reviews, those often have an IMD hump (though not sure to what extent it's actually audible). I do want to build something that would measure well.
But I'm thinking some enclosure, perhaps from Modushop (what I used for my Purifi amp), build in a RPi with USB and Ethernet/WiFi/Bluetooth, and then an internal DAC (balanced outputs a must) as well that I'd then need to figure out how to have the RPi communicate with the DAC and produce sound. And then a small display that shows track info, as well as some details like sample rate and bit depth. Maybe even a small color screen that shows album art.
Off the shelf will be much easier, but it's fun to build things and figure out how to make it all work. Last year I learned how to solder circuit boards.