Ethernet vs 5G Streamer Tech Considerations for Sound Quality

Mitch2 sounds like you had a fair amount work and expense getting main system set. I do have an orbi system as well but my main router signal is solid so I use that, less “devices” touching path I guess.
thyname, of course I can do A/B/A and have, didn’t need that wisdom smh....was just seeing if anyone had any hard data or justification for all the optical rendu and $1000 ethernet cable proponents vs 5G which is indeed a zero additional cost.

I have two situations.
Main System - From my modem-router location to my main system requires about 40+ feet of hard cabling allowing for how the cable must be run. Initially, I ran 50 feet of hardwired Ethernet cable and recently replaced that with 15M of fiber using two converters, one at the modem-router location and one at my main system that I use with a LPS. 
I have a second system located in my garage that provides music to our outdoor area.  That system is much further from my modem-router location.  A year or so ago, I switched my router to an Orbi mesh system.  The mesh system provides full internet bandwidth from multiple satellites that can be positioned wherever you choose.  By positioning one of the satellites in the garage, I was able to hardwire a very short Ethernet cable from that Orbi satellite to a second Roon endpoint that feeds the garage system from my hardwired server.  

Experiment #1: plug Ethernet cable. Listen

Experiment #2: unplug Ethernet cable, connect via WiFi. Listen

Then use whichever method of connection you like more going forward. 
If you hear no difference, use whichever is most convenient for you.

That is all you need. All that you can do yourself. Why search for technically documented justification in the Internets?

The Cary unit has a R2R DAC in it that I am using so no digital cables needed. Thanks for info and understanding the question. Way more than enough capacity so seems like 5G would be preferable.

 I am  looking for technical reasons why ethernet would be better for sound quality than solid 5G. Aforementioned possible ota interference is one possibility. Can’t find much/any technically documented justification or comparisons.

CD quality stream is 1.4Mbps.  4G is 100Mbps.  5G is 10Gbps.  The question is how you plan to feed it into DAC?

Ethernet cable is copper. Electricity can travel through copper. Along with noise. Two kinds of noise: Leakage—both high-impedance and low-impedance, and clock phase-noise. Ethernet transmission itself does not prevent the “trespassing” of these “noises”. Nothing magic about it. 
Really though, you have to experiment for yourself. Whichever sounds best to you. Experimenting for you requires nothing to be purchased. Zero cost experimentation 

Yes unit has antenna and signal is excellent. So you are saying antenna may pick up extraneous noise around the frequency it is designed for...definitely possible..although I am in a fairly uncongested area. Wonder how noise would compare with cable. Most of what I have read talks about the cables and noise and lots of people selling expensive ethernet cables. @eric squires, if ethernet is inherently balanced why all the $ spent upgrading wires, switches etc ?

How exactly are you running 5G on your Cary DMS-700? Does it have wi-fi connection?

And if it does, you realize it’s basically an antenna that captures the signal, right? Any antenna, is an antenna, and subject to potential noise associated with off-air signal transmission 

Ethernet is inherently balanced for low EMI/RFI pickup and galvanically isolated.

Use whichever you like.