Agree to not waste $$$ upgrading the Mac. I’d recommend the Innuos Pulse Mini for $1449, and now or later add an external linear power supply from LHY, SBooster, or Teddy Pardo (around $400) for a significant performance boost and you’ll have an excellent sounding streamer for about $2k. The bonus is it comes with their Sense app that’s widely regarded as the most user friendly out there, and some have even left Roon it’s so good — this is not a small consideration if ease of use is important to you. Innuos also offers excellent customer support if you hit a snag and is again not a small consideration. Also, just buy a tablet and download the Qobuz app (see link below). It’s not hard or expensive, and just have someone help you if need be — it literally takes like 5 minutes and well worth the effort as it will improve your quality of life significantly. Hope this helps, and best of luck.
https://www.dedicatedaudio.com/products/pulsemini-streaming-network-player-by-innuos
https://www.amazon.com/Apple-iPad-11-inch-Display-All-Day/dp/B0DZ75TN5F