Cable info

Depends on your budget.
Node2 is only $500 so would not make sense to spend same again on RCA cables. The nordost heimdal are probably over 1k new and I doubt the node2 dac is any different to the vault2 DAC.
I know the Mytek liberty is about 1k new the Brooklyn about $2200 new so it all depends how far you want to go.

I did extensive a-b comparison between rca out and spdif out from my vault 2 using same nordost heimdal series interconnect.
There really was NO comparison in my system.
But you are looking at 2k for a Brooklyn so.......

Mytek Liberty or Brooklyn both have MQA built in and are a MASSIVE upgrade on the Bluesound built in DAC.