I added a temporary ethernet cable snaking through the house, which cured the problem, but I feel the WiFi signal sounded better. I can't put my finger on it, but I'll do some more listening.
You should consider adding a Mesh node or Wi-Fi extender in your listening room and running a shorter (and better) Ethernet cable from that to the Node. It’s possible the long (and likely cheap) Ethernet cable was compromising performance as the direct connection should sound better than Wi-Fi as it avoids the Node from having to convert the Wi-Fi signal. Many here have done this and found significant improvements over Wi-Fi, and it appears the Wi-Fi receivers in streamers compromise sound so this is well worth a try as it’s not expensive. If you decide to try this, here is a good Ethernet cable that’s not too pricey and has been recommended highly here before. Hope this helps.