Just do what is convenient and with what equipment is at hand - sound quality issues are as close to inaudible via different routes as to not matter.

Remember that using CDs is now obsolete - Sonos offers a better way using wireless NAS. And even that has been largely obsoleted by streaming services.

So don’t spend too much to get an obsolete route to playing digital music to work - is what I am trying to convey.

If your transport has no built-in DAC then you’d need to add one. 

The S/PDIF coax on the Port is an output. The inputs on Port are analog.

Actually CDs are having a resurgence right now, and there are new players and transports available that have much better sound than the ones available a few years ago.

Also, I like collecting them and having something tangible in my hands (like the artwork, booklet, etc) improves my listening experience.

The transport doesn’t have a DAC, I will have an external one.

Thanks for the clarification regarding the Port.