any suggestions on what to replace Bluesound Node 2i with

OP, I have a Node 2 and a similar receiver, the Anthem 720 playing 5.1 for HT. I also use the receiver's dac only because I was forced to do so as I didn't want to use the Node's dac and have the Anthem still convert through it's circuitry when using the Anthem Room Correction. You sort of have to use one or the other to get the best case. I don't know if you'll be using the Room Correction of your Anthem 1120 but for me, I am and that is a big reason I am not upgrading for something like a T2 or similar piece and just keep using the Anthem's dac. 

I was tempted to just get something like the T2 and just see how it sounds even though the Anthem will still mess with the T2's sound while it corrects for the room, but I'm still not convinced that's the best idea. 

Good luck

+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Personally, I was waiting for a newer version of the Anthem str before I pulled the trigger or something else that has its functionality but is a notch or two better.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.