any suggestions on what to replace Bluesound Node 2i with

Personally I have not heard significant differences between streamers to same DAC with CD res sources. . Never heard a bad one. Interface type used can matter. Asynchronous USB is the way to go with most modern DACs. I only use wireless internet connections to isolate the streamer from any noise that might exist on a wired connection and find that works great though some claim a good wired internet connection is better at least in some cases perhaps with hi res sources where wireless bandwidth perhaps could come into play.

You might also explore Small Green Computer & Roon solution.  You could get a SGC Sonic Transport i5, Optical Rendu or Microrendu and a Roon license for ~$3K. 

I did the upgrade last year and went from a Node 2i running into the Chord Qutest and I replaced the Node 2i with an Innuos Zen mkIII going into the same Qutest via USB. Streaming Qobuz. To those doubting you can't hear a difference in streamers, I am sorry to say there was a big difference going through the Zen. Bigger soundstage, both depth and width, dynamics had more body, less digital glare and harshness on female vocals. The Innuos just has a greater sense of realism, you can hear deeper into the music. The Innuos products are amazing streamers, not to mention their server ability to easily rip CD's to the internal library is insanely quick and easy. They just released their new 2.0 which for me will replace Roon. But there absolutely was a difference and it was far from subtle. 

+1 for Wolf Audio. Customer service is excellent.

so the op evidently wants a new combo streamer/dac unit in a single box, as the lumin units are just that...

entry level lumin d2 runs a pair of wolfson bitstream dac chips and uses a solid state analog output driver stage... iirc the d2 is not transformer coupled like the higher lumin units

next up t2 runs ess sabre 9028 bitstream dac chip, has adjustable volume control (nice feature), and i believe the output stage is transformer coupled at the xlr outs so nice smoothing of the sound there...

either should be a fairly decent sonic upgrade over the sound of the node 2i heard at its rather murky analog outputs (albeit at fairly significant add’l expense)