Improving on the stream of a combined streamer dac

There are several possible culprits -

1. Your network card/streamer in the ECM is not that great

2. The Luna Orange Ethernet cable is not that great

3. The master on streamed and downloaded albums isn’t exactly the same

Does the SGC have a digital out that you can use to feed the DAC? That would allow you to compare network card in ECM to a streamer via USB or Coax. 
Also, try to swap Ethernet cables - put the Purist on ECM and Luna Orange (never heard of this cable brand by the way) to feed SGC. Purist is a good cable for the money  Trendnet switch is fine (I use the 8 port 1g unmanaged in my system with no sound degradation). Experiment with different combinations. If ECM using its built in streamer is consistently worse, then you should probably consider picking up a good separate streamer  

" So, I started looking at old audiogon threads to see if I could figure a quick and easy fix to up the sound of the streamer but found little that made sense or was affordable.  My question is whether I should continue to search, or if I should take it for what its worth and just listen to the music." So, you did not find any answers that were affordable or made sense to you and you do not know if to keep looking. This in itself does not make sense. Unfortunately going up the ladder of audio systems sound improvements could be quite expensive. I would suggest ethernet filter like Network Acoustics ENO2.

I stream Tidal via Roon.

I had Qobuz for a while which sounded better, but it often would drop out or stall.

Luna is a Montreal based cable company that specializes in tinned copper.

This upgraded Wiim amp ultra may be a good solution. You just need a pair speakers. Streaming is very solid and navigation is easy. Wiim fully supports Tidal. It's affordable and sounds world class. Alex/Wavetouch audio

Upgraded Wiim Amp Ultra, all-in-one streamer + DAC +Amp

There are digital front end tweeks that make a big difference in my systems.

First, a high quality audiophile switch in the chain before your server.  You can keep your existing switch and send one feed to a nice switch like the Network Acoustics Tempus, GTT DeJitterit, or JCAT M12.  Then feed your audio.  Use good LAN cables between your switch and audio equipment.  Finally, as @knock1 says, an ethernet filter.  I like the Network Acoustics Muon Pro, These upgrades, at this level, are good to stay with whatever streamer or DAC you choose down the road.

Start with one of them...you should easily hear it.