Talk to me about CAT 6 in wall cable

Cat6a is fine - and you would be hard pressed to outgrow its capabilities.  There is no current approved standard beyond 6a I believe -- there are cat7 and cat8 cables available - but none are standardized as there is no agreed upon data transfer standard yet. 

Did you think there were other options? cat5 is going backwards in terms of data capacity ... so cat6a would be my suggestion.

I have run hundreds of feet of 6a in my house for my network - and I have never out paced its capabilities.

I don't think the aurender has a fiber connection. which would be my only suggestion beyond a cat6 connection.   

Not sure what sort of network you have set up at home -- but I would highly suggest at least enterprise networking gear capable of 10gig. Once I abandoned consumer grade networking gear - it has never been better.  Signal packets were far more consistent, streaming was far and above what it was - and yes - I could tell a difference. I realize most if not all audio gear network capabilities is still 1gb at most -- but might as well lay down the foundation and infrastructure for future use.

Hard to justify long runs of basic quality in-wall cable these days, when you have mesh networks that enable high speed internet throughput the house plus ability to run shorter, high quality cable. Just my opinion…others may disagree. 

Not all are the same, some are 8 strands of 26 awg, others 24 awg, still others, harder to find, are 22 awg. Some are stranded, some are solid core.

they add up to different awg when combined, (i.e. speaker cables)

https://www.wirebarn.com/Combined-Wire-Gauge-Calculator_ep_42.html

some have separate insulation for each pair, and separately foil wrap the 8.

not a recommendation, just found it quickly to illustrate 

https://www.ebay.com/itm/166916664863?_skw=cat+6+22+awg&itmmeta=01KWW6MJN4N45WC7ASSQTNW9MP&hash=item26dd022e1f:g:X2MAAOSwQY5mus4d&itmprp=enc%3AAQALAAAA0GfYFPkwiKCW4ZNSs2u11xDN6Obs1kTDO9WCBlmuuiMeoEV7ffVQukCvKLBcWWjeI6fp4e6HOKobJM5oDJzLEfoL23K0X%2FrDHq3OX2gnsFH7sPzOtz78ZTGZBKU6fjDykgiRFOYkc0BJMJWBA%2BA3%2FRkLzbagb9aBRhUvlATm4pvJHyMFfs36enWLjujXiWGfPEmUyqfqI%2FHk6pj%2BTt8PfkLTPipYBCNUOR9GhQGHhaVaaXo2u%2BYJPmDUa0L9zpKAGNV2ZtAbXl8O8238GpvtVzI%3D%7Ctkp%3ABk9SR9qq0obnZw

also, some come in a variety of colors, which can make it easier later to identify what's what. (or mark ends with different colors or numbers.