any suggestions on what to replace Bluesound Node 2i with

I am doing a major upgrade on my home theater system. I want to upgrade my streamer. I can spend around $4500 if I have to. My dealer played a Lumin T2 and the music, Tidal, sounded amazing. He said I would be okay with the D2 if I wanted to save money
Any one have any experience with the the Lumin's. I am open to other streamers, it does not have to be Lumin. Thanks 
Innuos Zen mkIII or Zenith mkIII. That is the upgrade I did last year. I went from a Node 2i to a Zen mkIII. The Node is a great piece for its price range, but the Innuos Zen is in a whole different class. I loved it so much that last week I sold my Zen and went to a Zenith. Watch John Darko's review of the Zen. 
thanks I will check out the Zenith

I’m a very happy T2 user. 

Don’t forget it’s everything, especially including the room, that effects sound. 

The T2 has a good DAC chip in it. A DAC is mandatory. Don’t rock out at home with out one. 

You might find not much a difference between any mid range priced units. To me most all sound good. I’ve listened to maybe eight?
Some say that there are implementations of the Raspberry Pi that are better than other options.
The Raspberry Pi 4’s wired Ethernet doesn’t share the USB bus like in the previous versions. Otherwise, if you used a USB DAC with a Pi 3 B+ and streamed the file over the network using a physical connection (like my setup) you’d encounter random drop outs. There is a fix - reducing the link speed to 100 Mb/s - but it requires some technical knowledge.

Otherwise, I honestly can’t tell the difference between something streamed from my Pi or played from the Oppo UDP-203 with VanityHD board. They both sound equally good over the Benchmark DAC3.
op needs to be more precise... is he replacing the node 2i being used as streamer and dac (e.g. using its analog rca outputs) or is he seeking just a streamer upgrade only...

case 1 makes sense, maybe get a better outboard dac put it downstream of the node

case 2 may be $ spent with limited sq upgrade