If you read the specifications published by Spotify here Technical Requirements | Spotify for Developers you will see that it is mandatory for a Spotify capable device to communicate with Spotify regardless of the state of a Spotify “input”.
In other words, you can’t switch off Spotify. You might mark the option as disabled, but it is mandatory that communication still occurs.
I suspect Tidal place the same requirements on a device supporting tidal connect.
These devices were never designed to completely function “off grid”; hence paranoia apparently occurs when someone discovers their streamer is trying to reach the outside world when they (the owner) are trying to lock it down.
ND5XS2 - Tuned off but reaching out to WAN over TCP? - #4 by chrisgtl