Do I need a new DAC/streamer. Considering?

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. 

While I cannot explain why djones51 has not experienced favorable results, many of us have.  The streamer is likely as important and impactful as the DAC - a result supported by direct experience.  I can imagine that some systems will see less benefit, but in my own system - the differences in upgrading over the Node 2 (going into an outboard DAC) were clear and favorable.  So, the only way for the OP to know - is to try one in their own system.

The reason is blind listening. You'll be surprised how alike streamers not using internal dacs sound or if you understood digital transfer you really wouldn't be surprised at all.