My router is on a separate floor from the system and I currently run eero mesh to strengthen the signal to the other floor (basement). So is using an Ethernet cable still possible?
Absolutely. You just need another Mesh node near your streamer and run an Ethernet cable from that node to the streamer and USB from the streamer to your DAC and you’re golden for streaming. Using the Node as an example, you can then just run a USB cable from your external drive into the Node and now all your music will be available from the Node. You’re very close since you already have Mesh and music on an external drive.