Streaming Transport without DAC- few choices

There are at least about 2 dozen I know of so your premise is false and under researched.
$200 of RasPi will blow away a Mac.

If I didn't have a Blusound Node, I'd do a Raspberry Pi. 

https://www.youtube.com/watch?v=2fX7NSaAKYU&ab_channel=TheHansBeekhuyzenChannel

https://darko.audio/2020/01/raspberry-pi-audio-streaming-101/

Sonore opticalRendu or ultraRendu

Lumin U1 Mini — most dealers will discount and bring it under 2k

iFi just released their new ZEN Stream which looks nicely done for $399 .. WiFi & ethernet connections, USB & SPDIF out, and sans DAC to name a few features.

https://ifi-audio.com/products/zen-stream/

If you're interested in Roon, they have a Nucleus which hosts their software and acts as a streamer for $1500.

At one point in time I had a mac mini with audirvana feeding a Berkeley alpha usb which was feeding a Berkeley alpha dac. Out of boredom I purchased a Raspberry PI and installed Roppieexl to try streaming. I then compared the direct Mac connection with the Mac streaming to the Raspberry pi connected to the Berkely. I found minimal sound differences between the two setups.

op

you mean a streamer, or a transport?

you said 'transport' in your title, that means something that will spin a cd and read the bits on it...

I’m very satisfied with the sound of the $800 Pro-ject Stream Box Ultra S2. It’s based on a Raspberry Pi with the power supplies and analog sections optimized for low noise. It certainly sounds better than a laptop or iPhone that I used for a short while. At some time if I get bored with time on my hands, I’ll compare it to more expensive streamer/transports to see if anything else sounds better. I'm thinking Innuos or Auralic. I’ve heard the Naim NDX 2 used to play back local files from a flash drive through my Pontus II DAC. It sounded good, but wasn’t noticeably better (at least without comparing head-to-head with my Pro-ject streamer).

You can plug a hard drive, solid state drive or flash drive into the Pro-ject streamer so it becomes a transport for local files.

The Innuos Zen Mini is supposed to be quite good as well.

In theory, a dedicated streamer will have less EMI and RFI than a Mac Mini or other general purpose computing device. Maybe buy a streamer used and see how it works for your needs?

The Innuos Zen Mini has a DAC, so I’d recommend its big brother the Zen Mk3 that’ll stream but also has onboard CD drive and storage so you can easily load all your CDs directly into it and have access to all your music through one device.  Anyway, that’s what I’d do FWIW, but best of luck with whatever you decide. 

I trialed a used Primare NP5 to good effect. Simple, small footprint, clean delivery.

Mac mini may sound purdy good. But dealing with all the patches/security upgrades is a headache. Go for a dedicated streamer. +1 on the Raspberry Pi. I found a Bryston BDP Pi used for $500 (basically a Raspberry Pi). Manic Moose interface is spartan at best but the SQ is excellent. You can get a SGC Sonic Transport and Micro Rendu for less than $2K. Run The Roons or BubbleUPnP.