USB and Coaxial at the same time?

No but it would be weird and not a direct comparison. As soon as you connect the USB it may tru to take over the streamers clock.

A better comparison will be to do each separately

When I compared USB to coax on my N200 I was running one interface at a time and was taking it slow evaluating sonic quantities of each listening to complete songs or even more than one song with each.
I don’t recommend switching back and forth to quickly A/B. That is a waste of time and effort - you won’t have enough to go on. 

Well to be clear, I highly prefer USB. But I was wondering if on some of the older Rock recordings if switching to coaxial may smooth it out a bit. I just wanted to try it and see what happens.

It might smooth it out. 

When comparing USB and coaxial audio connections for music, USB generally offers more flexibility and potential for higher quality sound due to its ability to handle higher bitrates and asynchronous data transfer, while coaxial may be preferred by some audiophiles for its perceived simplicity and lower jitter, depending on the quality of the implementation in both devices; ultimately, the best choice depends on your specific setup and personal preference. 

...the humble opinion of a Google AI when posted the query....

...at the risk of throwing some lighter fluid on the analog v. digital fray....

Whereas, in adding HDMI to the caldron:

AI Overview

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Optical and HDMI cables are both used to transmit digital audio from one device to another. HDMI cables can also transmit video signals. The main difference between the two is the number of audio formats they support. 

Audio formats 

• Optical: Supports 5.1 Dolby Digital and DTS audio
• HDMI: Supports 5.1 Dolby Digital and DTS audio, plus Dolby Digital Plus, Dolby True HD, DTS-HD Master Audio, Dolby Atmos, and DTS:X

Video signals 

• Optical: Transmits audio only
• HDMI: Transmits both audio and video

Compatibility

• HDMI: Modern versions of HDMI, like 2.0 and 2.1, are compatible with modern technologies 
• Optical: Optical cables are a good choice for older devices 

Reliability 

• Optical: Optical cables are known for being reliable and resistant to interference

Ease of use 

• HDMI: HDMI can be a good choice if you want to use a single cable between two devices

Surround sound 

• HDMI ARC: HDMI ARC can support 5.1 surround sound channels with enhanced sound quality

• HDMI vs Optical - Klipsch Support

  Both HDMI and optical pass digital audio from one device to another. Both are better than analog (the red and white cables). Both ... 

'Generative AI is experimental' 

(...my hashmarks' )

....considering implementing all 3 since I can, just to see if my 20th century trash can deal with being dragged into the 21st.....

... I can hear their tinny little voices already.....

"...no....No...NO....NOOOOOO....We're not worthy!!!!"

*Shuddup,,,*