Stepping up from a SonicTransporter i5 / UltraRendu

I’m using the i5/UD into a Denafrips GAIA DDC and original Terminator DAC with latest DSP.

I’d like to:

A-Take the sound quality to a higher level 

B- simplify the system by dropping the i5, UD and possibly the DDC

I’d consider a fileserver sans DAC like the Innuos Zenith MkIII or dropping the Terminator and buying a one box server/DAC.

 I don’t stream from any services so it would be nice to drop Roon, too. 
 

I want to add digital to a second system in an adjoining room so buying hardware that might enable me to power a second, remote DAC would be a nice bonus. Or does a one-box solution for this exist?

 I can put around $5k into whatever funds I can get from the sale of existing hardware. 

My music is on a 8tb USB drive.

I don’t want to go through a major overhaul for a small improvement. I like the sound of the Terminator a lot, so wouldn’t mind keeping it if I thought something like the Innuos Zenith would provide the step up I’m looking for, but I’m not sure that it will. An opinion from someone who has moved on/up from an i5 UltraRendu would be great!

Thanks in advance for any insights!