any suggestions on what to replace Bluesound Node 2i with

Honestly, what you need is a better DAC at this point, not a new streamer. Get yourself a Denafrips Ares II for around $700 and then evaluate the streamer question. 

+2 for big_greg's and other's suggestion re a preamp with ht bypass. This is also what I'm looking at after steering away from the Lumin T2s... dedicated option. Something like the Anthem str preamp has the ht bypass and a relative good dac and most importantly for the op (and me), it will still do ARC room correction.  It will also calibrate 2 subwoofers independently, which is what I have as well as the op. 
Personally, I was waiting for a newer version of the Anthem str before I pulled the trigger or something else that has its functionality but is a notch or two better. But for the op, he really needs to decide if the lumin t2's dac is similar in sound performance to the dac in the Anthem str in this case.

I also looked into the mini dsp HD that was mentioned above. That seemed to do what the op is looking for. 
Also, Roon with the convolution files for room correction would work, but unsure of how many boxes that would need. With someone already having a ht system, I am personally trying to keep box count down.
The main point fir the above is if you're keeping room correction,  you can't just add a dac.
Good luck.

I used a Nativ Vita with Roon to a McIntosh C40 and an NAD amp.  Loved it - sold the McIntosh and NAD and bought NAD M33 w/ BluOS - - love it more - claims to be Roon ready but I haven’t been able to do that.  But integrated BluOS in the NAD along with Quobuz and Tidal are seamless and excellent sound quality.  I am proud owner user of often bashed but excellent and inexpensive Tekton speakers which certainly add to the sound quality of my system.  

 

I upgraded the board and PSU on my 2i. Used PD Creative in Poland, and an Allo Shanti LSPU. It added more transparency, more detail in the treble, more defined bass, but did slightly remove some of the warmth of the standard system. There was a slight bump in the upper mid range, but overall I really like it, and made a big difference. I am not using an external DAC yet. 

I went to my dealer's showroom to check out the Lumin T2 again and I am sold on it. Pricey but I think it will be worth the money