What about just purchasing software for your Mac - Roon and HQ player? You can then either go straight into a network ready DAC or purchase an endpoint - like Sonore - to "convert" the ethernet into USB for a USB DAC. Roon and HQ player will cost you under $1K to purchase and are loaded with features, including some very high level filters in HQ player
I am new to digital, but the last millennium CD player always worked fine.
However the amount of computer noise I had recently using my new DAC as an ADC was astounding.
So I am not sure any old computer makes for a de facto good starting point??
Are those all in one solutions like a TDAI with the Roon player built in worthwhile?
(Or worthwhile is one needs an amp and player?)