Upgrade your Node first. The Node can be improved by a good margin by upgrading the internal power supply with a PD Creative board - https://pd-cf.com/.../bluesound-node-2-2i-upgrade-low.../
I power this board with a SBooster LPS. Takes the node to a level that you would need to spend $$$ on to achieve. And as others have said, a better DAC will then keep you happy for a long time.