Pls Recommend Streamer Under $500 for Tidal “HiFi”

I’m searching for the best sounding streamer under $500 that supports Tidal’s “HiFi” lossless playback. I understand that r2r DAC is desirable, and if possible, I’d like to use the streamer as a DAC for my CD transport and play and store files from my NAS. The unit doesn’t need to have a preamp / integrated amp as I’ll be connecting it to my existing preamp which is feeding vertically bi-amped Energy Reference Connoisseur 70 speakers. Thanks for your suggestions!
You should checkout the PecanPi Streamer from Orchard Audio.  Leo was very helpful with all my questions. I have been very satisfied with my purchase.  I use as a Roon end-point and stream from tidal.
Good choice. I'm using one for one of my Roon endpoints and plan to get a couple more for other zones in my house. 
I have a similiar set up to double-dutch above.  I use a Raspberry Pi3b
(Raspberry has the Pi4 now but the 3 is more than sufficient) with a
Pi2 Design 502 Dac, with a case from their web site. $124. This can be used as a stand alone dac but is better to use for SPDIF out. I run that with Moode software, just download onto a MicroSD card and run.  Easy.  This goes into a Schiit Modi r2r Dac. $250. I run a Bubble Upnp app on Android phone or LUMIN on iPad.  You’ll need a digital cable also.  I lived with this set up for a couple years on my highly resolving system, and I don’t think you can do better for under $500.
Pi2 Design has a newer hat for a little more also. Check their web site.
All this stuff requires a DIY approach, but it isn’t difficult, and probably sounds better than commercial stuff much priced higher.
Put it this way, I upgraded the Dac to the Schiit Yggdrasil and the Raspberry / Pi2 Design setup has not held it back at all.
 I can actually hear differences between different digital connections.