Do I need a new DAC/streamer. Considering?

Given the rest of your equipment, I would definitely entertain a Lumin X-1.  I have had the D-2, A-1, U-1 mini and the X-1.  you can sell off the your other digital equipment and just use the X-1.  I just sold my X-1 because I wanted a Tube DAC to go along with the rest of my tube amps.  I bought the Lampi Pacific at three times the cost.  I will say the X-1 is a very close second.  

I had a separate DAC, Music Server and Transporter.  I was able to sell them all and just go with the Lumin  X-1.  The sound is really really good.  The App is so easy to use and you don't need Roon.  I did have a 4tb Synology NAS where all of my music is filed.  I think the Lumin X-1 is the best DAC / Streamer under $19k.  They show up on the used market occasionally.  

I recommend Aurender N100C, that would pair well with your C53’s internal DAC. Aurender’s Conductor app is also excellent. It would be a worthy upgrade over Node 2i. 

I only stream music. I don’t play disc or records 

I bought a Lumin T2 a couple of weeks ago and use its DAC as opposed to the Mac C2600. In your case, the C53 supposedly has a much better DAC and upgradable in the future, so I would recommend to just get the Lumin U1 Mini streamer which will be a step up from the BS. The Lumin app is decent but I prefer to use  Roon. I do not have any experience with Aurender. It was not in consideration because I needed MQA decoding. 

Do you like the Node2i? The user interface and the connections suit your needs? If so just keep using it, if you have an itch to try something else the Lumin U1 mini or Bel Canto estream are choices you could return if they aren't to your liking. I've tried about 8 streamers as far as sound quality there isn't a dimes worth of difference using them connected to the same DAC. I ended up with the Lumin U1 mini not because it sounds any better but I like the user interface and it had the AES3 connection I needed.