Is the Mytek Brooklyn Bridge or Lumin D2 good buys in 2021?

I don’t think my reply is a complete non-sequitor, @jackd, at least a third of the OP's post described issues with the DAC’s he is auditioning have to do with the streaming software and control.

Honestly, using Roon, I never touch my DAC.

Erik

The D2 is the entry level combo product from one of the long time leaders in the streaming industry who developed and continues to update their product on a regular basis so at least you have software support with a no nonsense design and build. They Mytek because of their use of the "contracted" Mconnect app I wouldn't  touch. So if he bought them to be a Streamer/Dac and he thinks they sound similar then always go with the better homegrown app regardless of the aftermarket apps. I would expect that the streamer guts of the Mytek to be nothing more than the Conversdigital board used by PSA, Ayre and many others. One of the reasons that in the end I steered clear of the Innuos products until their own app is finished and market tested. 

OP here - I don’t have a use case for Roon. All the albums I want to listen to are on Tidal, which is my exclusive source.  The Elac’s are active but 100% analog when connected via xlr/rca. Not interested in a pre-amp or separate dac. No sub. Just want a single box for good sounding music.

Right now I’m leaning towards the Lumin D2. The app is much, MUCH better than mConnect.  Also, the Mytek sounds a bit harsh and thin to my ears. That configurable “M” diode those is so cool looking.

Might keep both.

One of my big fears is not that the DAC will get outdated, as everything after 2015 or so is really excellent, but that the software will.
I don't need more resolution, or higher bandwidth, but I am worried about the churn in streaming services.  Like, what happens when Tidal and Quboz vanishes, and there's what's next? Will my streamer be updated?

For those reasons, I finally, begrudgingly, kicking and screaming, ended up with a subscription software service.  I also feel I have some amount of power.  If Roon stops updating in a way I like, I stop paying for it.

As long as Lumin exists in the market then Peter and his team will continue to update the software and be available to assist with questions on multiple forums.  Since their parent company is a big player in the digital tv market in the Far East they are not going anywhere. Of the choices you have on hand the D2 is where I would put my money. The D2 is in fact a second generation device so not really dated.