Updating My Digital System

Welcome to the wonderful world of Digital improvement @kevinjvl !  You have a very nice Esoteric DAC.  You need to feed it quality, low noise digital.  Many ways to improve over what you had, being Airplay from a computer.  Airplay is notoriously poor, and the Mac Mini is forced to run numerous behind the scene processes that add noise.  A good streamer or bdige is the first thing to acquire.  After that, quality ethernet cables (especially the last one going into the streamer), a good audiophile switch with a good linear power supply (before the streamer), and a good cable from streamer to DAC all improve things.  Bit perfect is not the key term here.

Many will tell you none of this matters, but your ears will be the decision maker, as they already have!

BTW from AI on Airplay:

AirPlay 2 generally streams audio at 16-bit/44.1 kHz (CD quality) using the Apple Lossless Audio Codec (ALAC), though it can support up to 24-bit/48 kHz in some cases. While capable of lossless audio, AirPlay 2 often downsamples or compresses Apple Music streams to 256 kbps AAC. It does not support high-resolution audio (e.g., 24-bit/96 kHz or higher).

Our HP Elitedesk mini PC setup using jriver media center via USB connected to a Denafrips Hermes to our modified Directstream DAC via i2s sounds much better than a dedicated streamer so the assumption that a streamer is always better than a PC is false. If you do the PC correctly it is unbeatable. Also jriver supports many more file formats including SACD iso's. We also compared Roon with jriver and we feel jriver is superior. No matter what you use to stream with we found that using fiber media converters for the ethernet connection is a big plus as it adds additional isolation.  

I also noticed a major improvement when I went from an iPad pro to an Innuos Stream 1 (with LPS1 and Phoenix USB module).  Better definition, lower noise floor, better timbre and tonal qualities of instruments and voices.  I also upgraded my cabling, using DH Labs Mirage for the USB connection and Reunion Cat 8 for Ethernet, both an upgrade over more modest cabling.

@jk_richards I’m not saying you’re right or wrong but have you tried a good streamer and DAC, Ethernet filtration, high grade Ethernet cable(s) and a quite switch? Taking care of the whole digital chain I found that better than from a computer. Naturally YMMV.