dac and streamer or seperates

All the ’high end’ (apparently!) "streamers" are essentially SBC PCs. If you educate yourself on how to build a "audio optimized" PC, you will have all the freedom in the world wrt choice of hardware and software optimization. But, if you buy a ’high end’ (apparently!) streamer, i.e., have some other dude do some work for you and put a brand name on it, you will just fatten his wallet and be locked into any crap he gave you.

If you have hires files that you just plan to stream from a nas, or tidal/qobuz. forget about a streamer and get a streaming enabled high quality DAC such as the Gustard R26 --> use with bubbleupnp on any android device. You could have some jaw dropping sound quality at this kind of price...

I would recommend Aurender NH150 and Schiit Yggdrasil. Works well for me!

@vonhelmholtz 

saw a Bryston BDA 3 over on USAudio for $1.5K that might pair well with the Air Lens. Bring you in under $4K. 

The Krell DAC is not that bad (ES9028PRO Sabre) $1K option correct? and I can only imagine they wouldn’t slack on the implementation, check it out here where they compare it to a comparable priced external.

https://www.stereophile.com/content/krell-k-300i-integrated-amplifier-page-2

You might want to get a nice streamer and run it through there first. Then demo external  DACS 

I’ve just finished my journey down the same path as you’re heading now. I started with a modded Cambridge cxn v2, modded by ModWright. Excellent sound and the streaming end is absolutely seamless. I’ve never had a streaming glitch in over a year. 
I decided I wanted a little different sound and now have separates. I spent more on the dac, by a lot, and decided to go with the LUMIN u2 mini as the streamer. Great unit and it will sell quickly when I upgrade in the future. Definitely keep resale in mind when purchasing. I would spend the bulk of cash on the dac. I purchased the Rockna Wavedream and it’s a tremendous difference. Hard to tell how much the LUMIN added. Anyway, you can always spend a grand or so on a good streamer. Try to find a new model since improvements are coming fast and furious in that price range. 
Perhaps a Benchmark/LUMIN u2 mini would be perfect?