How would you spend my next $5K?

Room is the issue for me to add components, but for the money, eh, maybe a bit more, a Naim Uniti with a 20 terabyte drive.  A local dealer that sells it would include his entire library, 16 terabytes of hi def music.  Music of every kind mostly ripped from the thousands of LPs they have and a host of other things that would take too long to describe.

Extra S/812 sub and some bass traps. After that, change out all your Transparent cables. They all add to muddiness of the bass. No bass detail albeit they add some airiness to the upper registers since they pressurize the room with their boominess. I’ve been extremely disappointed with Transparents. Most cables at 1/4-1/6 the price are much better.

I would do number 6 or 7 if u was in your shoes.

More music. You have arrived after moving everything away from the speakers, Great system by the way! 

I read a bit of this thread. One can have the best system. Though without proper acoustical set up. You are not optimizing your systems full potential. 
 

Yes. A new power cord or new speakers are fun. Though proper treatment of your room will make all extremely cohesive. 
 

best luck