Do I need a new DAC/streamer. Considering?

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. 

There is definitely no need for a DAC in the streaming device and the only question is whether you want a server between your streaming service and your player or you want to go straight to the player.  Streamers bypass the server and you are simply directing Tidal or Qobuz to your player.  This exposes your player to the volatility of the internet. 

If you have a server in place between player and streaming source (Tidal Qobuz) you get a more stable signal as the server brings in the track and then delivers it to the player. 

If you run Tidal or Qobuz through Roon, it undeniably sounds different than if you send it straight to your device.  I have recently tested this with Tidal through Roon to my 2Go/Hugo 2 vs sending the signal straight to the 2Go through Tidal.  I have a Roon Nucleus+ on my network.  The sound is a bit thinner in the midrange and airier in the treble when you go straight to the 2Go.  Far from ideal.  I found it quite different and found the 2Go was inferior when dealing with Tidal directly vs the Roon Nucleus+ handling it first.  I have no DSPs running in Roon.