Where should I go from here with my digital front end?

Thanks for the info on your system. Looks thoughtfully assembled with some good choices.

I don’t know, you have a pretty good setup. If you have $1K. I would save it and wait until you can invest in a better integrated amp as your next step. In the mean time I would work with your setup, room treatments. Enjoy what you have. Assuming you have a good quality power cord on your amp.

You can get small incremental improvements by fiddling with your network. But there are so many opportunities. All opportunities must be weighed… interconnects, power cables, isolation, set up, components.

Add this to your optical set up.  It made a nice improvement over the wall plugs.  It has two cables and can power both FMC’s.  Optical made a big difference for my system.
 

The Eno filter made a big difference in my system. (Router>.5 ft Cat 8> switch > 30 ft Cat 8 > ENO > Streamer)

@emil 

Another vote for ENO passive filter, they do offer 30 days return policy. 

If you haven't used good feet to isolate your gear, that can be a significant improvement. When I tried it under a DVD player used only as a CD drive it was like I bought a new unit for at least an order more magnitude. And while that was the biggest improvement, isolation under every piece of electronics was audible.