Seriously? Why Buy ARC Ref 6SE? seems Benchmark LA4 is a better choice.

Funny, I thought money was only in issue when two items performed identically in YOUR ROOM.

I would say this is a non-discussion.  Take both home, listen, and buy the one that sounds the best IN YOUR ROOM and that you can afford.

End of discussion.

Absolutely nailed it @mahler123

Here is what I think is a very good discussion about the importance of preamps. In many cases, they can make the single biggest differences of any component. They are not just "pass through" devices. In my experience they are truly interactive in nature and therefore very difficult to get right. They interact with interconnects, media sources, and the RF and other noise sources and do so at various voltage levels. The design of a good preamp is a great combination of science and art. Enjoy what you will...
Check this out- https://www.stereophile.com/content/rotel-michi-p5-preamplifier

Great article about preamp.

anybody ever see a more detailed overview of internal components and how all are connected together?

Sometimes you just need to chuckle. The original question was posed by someone who posits “And I don’t like listening to music very much“ ?  No further comment needed.  
Yyzsantabarbara hit the nail on the head.  The fun in any hobby is to increase your level of appreciation for the object of your enthusiasm.
That can be accomplished with music reproduction whether you are building a $5K or $50K system.  Not so true with cars.  Believe me, I know.