Kef LS50 Wireless - optimal configuration

 Hi there, 

I'm new to this forum, but I don't think this question has been answered before. 

My current set up is Sonos Connect + KEF LS50 Wireless + Kef Kube 10b. I'm using an optical cable to connect the Connect to the speakers. I stream through Spotify (Premium).

I love the set up, it's simple and works well for me. I'm wondering though, is the Sonos Connect holding back the system? Is there a straight forward upgrade that I'm missing out on or is this the best that this system can do? 

I've read that some people are adding external DACs and using the RCA inputs, that's off the table for me. 

I'd love the input and guidance.

Thank you
Have you connected the speakers to your wifi and gone through the settings on the kef control app?  If not, you’ll want to do this.

Next, I’d get a subscription to Tidal and use Tidal.  I’m not familiar with sonos, but If it supports Qobuz, that would be even better as the dac in the ls50’s supports 24/192.

Pretty noticeable difference between Spotify and Tidal though...
+1 on Tidal upgrading your streaming service would be the easiest and cheapest upgrade possible and the difference is very noticeable.
The Bluesound Node 2i would be an obvious upgrade but I totally agree that you should move to lossless streaming first.

The Connect sounds pretty good via it's optical output into an external dac on it's own.
The bluesound node 2i solves the main issue that I have with the LS50w, and that’s their horrible app...
Thanks everyone! I've signed up to Tidal, haven't had a chance to do any critical listening yet, but will do over the next few days.

Does the bluesound node 2i actually make a difference given that the LS50W are powered speakers? 

Thanks again to everyone who replied!
I don't want to hi-jack the thread but Im in a similar situation as the OP.  I just picked up the speakers and they sound great but man that app sucks!  I have been using Tidal through BT off my phone.  Will I get better SQ if I use a bluesound node or something other than my phone?
@asmithkash absolutley the Node and most other dedicated streamers will beat the sound from Bluetooth off your phone by a large margin.
so really going to a dedicated streamer is the trick then?  As i go higher like, a lumin or something like that it gets better?