@curiousjim
In my opinion going from a $2.000 retail DAC to a $4,000 retail DAC might not be as big of an improvement as you’d like. I’m going to estimate it will mostly be a different presentation with some very slight refinements. It’s a $2000-$5000 category.
To make a considerable improvement you would have to cross into another price bracket which is $6,000 up, retail. Or be patient and wait for a deal on a used market. A used $4000 DAC that retailed for $7,000-$8,000 new should be a good option.
I know you said you don’t need a built in preamp and or streamer. I would encourage you not to overlook some candidates that include one or both options.

