This is what helped my system. I'm sure you have done some of these things. I went for low cost options that ended up paying off.
Dedicated power line or if you use lots of power.
EMI/RFI filter on incoming power
EMI/RFI on router from internet Co.
EMI/RFI on ethernet cable to streamer.
Power cords
Good interconnects. Use contact enhancer. Stabilant 22 is reasonable.
Isolate speakers from floor. Spikes won't do it.
Use a good equipment rack
Isolate all components. I used Herbie's.
You could do this and then the DAC. Just my thoughts.