Point of diminishing returns for a Network Streamers?

First off, a general purpose Mac or laptop is not a ideal source for streaming from Qobuz or Tidal. 

Maybe not ... but a general purpose Mac is an ideal source for streaming from Apple Music. For some (not all) listeners, Apple Music may be preferable to Qobuz or Tidal.  Plus, a general purpose computer offers the option to run digital signal processing applications (such as HQ Player or BACCH4Mac.)  DSP is likely to have a much bigger impact on sound quality than your choice of streamers (assuming your streaming device isn't also performing DAC/preamp/other functions).

I usually prefer Qobuz/Tidal over AM, just because Roon does not  support Apple Music.  However, I still have a USB feed from a Mac Mini in order to run DSP (in addition to other music-related functions).  The Mac (or an Apple TV device) also allows you to display album art on a TV screen.

@abreryclark, if you like Roon I would stick with using a computer of some kind as your streamer.

The Gold Note DS 10 looks interesting

I went from streaming Tidal on an iPad to an Innuos Zen MkIII with Roon.

it was like going from a $100 MM cartridge to a $2000 MC cartridge.

I’ve read to where a nice higher end streamer will even make one’s mid tier Dac sound much more improved. The Lumin may be the way to go