Help setting up nework for Zenith mk3 arriving next week

Searching existing discussions here and in other forums has helped somewhat but not nearly enough for a computer-phobe like me.  In fact, it has almost raised as many questions as it has answered.  This discussion should help a great deal. 

For those that might be kind enough to offer insights and/or answer my questoins based on their 'adventures in computer audio' hopefully these specifics will help you help me and others searching this topic.

GEAR:

--Comcast issued modem/router.  If the model or technical specs matter, I can provide that.  Ethernet is running to tv in living room for streaming (no idea if that is relevant).
--one ethernet port currently available on the comcast modem/router
--Ethernet or fiber optic length to music room 100'-150' 
--Innuos Zenith mk3 
--Lyngdorf 2170 TDAI
--USB cable will connect Zenith to Lyngdorf
--Will stream Tidal or Qobuz and maybe play music stored on the Zenith SSD's.

MY DEALER'S NETWORK SUGGESTION:

It's very appealing for its simplicity:  Connect the modem and the Zenith with cat 6a (shielded cat 6) and run it into the music room thru a brush plate.  This avoids the add'l connections required when using a wall terminal plate.  He did not prescribe a brand of cat 6a or connectors but he suggests good quality for each.  That's it.  Done!   Or...AM I?

I don't know, which is why I started this discussion, my first on AG.

If I implement this approach, I will plan to purchase pre-terminated bluejean brand cat 6a and know the quality of all is rock-solid and it comes with a test report of your actual run.  About $1.20/ft.   BTW, BJ told me I only needed cat 5 or 5e ( don't recall which).  They said shielding is only needed when there are many other data-carrying wires next to each other.  There aren't in my case.  And the 5 is a lot less $.  But, I plan to err on the side of caution and do cat 6a anyway.

QUESTIONS:

1. Have others used a set up like this (described above) and been very pleased?
2. Can others please share ways of improving the SQ with enhancements of varying cost?
3. Anyone like something better than bluejean? 

Many report audible improvements from using short ethernet cables such as Supracat 8, Audioquest, etc, for the last meter or so.

4. Are they using those from their wall plate to the streamer?

5. If so, are they adding those at the end of a run of ordinary ethernet like BJ or are they running a more expensive ethernet the entire way from the modem/router (aka, gateway?) to the streamer.?  Over 100' in my case.

6.If the audiophile grade 1-1.5m (are they called patchcords?) aren't used from the wall plate to streamer, then wear are they used?  BTW, I realize I won't have a wall terminal plate if I follow my dealers suggestion.  But I presume there exists a coupler that I could use.

7.  Is buying my own modem/router to replace the comcast one beneficial?  If so...any suggestions.  Maybe Comcast would update my gateway.  My current one is 2-3 years old.

8.  Has anyone switched from ethernet to fiber optic and realized an improvement in SQ.  Any innuos users in particular?  I realize optical ethernet requires converters and upgraded power supplies for converters but I wonder if it is worth doing.  If so...it seems like the costs are very reasonable.


Thank you,