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 
galleybob
Have you tried a different connection than optical with the Bluesound?   That alone might make a difference. 
I’d be looking for a player better than BluOS. Many are.
+1 on the Ras Pi4 with piCore player.
Toslink isn't necessarily awful. With good glass it's better than coax with a middling cable.
You don't need to spend a lot for a good streamer. The Cambridge Audio Cxn v2 is a great streamer and also uses the Wolfson chips in it's Dac. Sounds great looks great and a bargain at $1099. It's also Roon ready.
I find Bluesound to be not as good as Control4 streaming to my Anthem. I am also thinking that Apple Lossless even though it is 12/44 is sounding better than Bluesound
Bluesound Node 2i is optical. I have tried it with RCA, and Coaxial. My best results by far have been optical. I find that HDMI has been better so that's why I am not using Bluesound. To be fair when I tested coaxial I used a $30 cable, I'm sure I would have had better results with a higher quality coaxial. The optical cable is the one that came with the Bluesound
I am doing a major upgrade on system so I am looking for a major upgrade to streaming. I stream Qobuz but now I also stream Apple Lossless