Stop notifications from News app on a particular news channel/topic

A news channel I have zero interest in keeps popping up notifications through the News app. I've verified I'm not following it. Its happening across all my devices (iPhone, iPad, watch, and Macbook Pro) all running the latest OSes, which makes me wonder if this setting is buried in iCloud somewhere.

Any suggestions on what where I can unmark this channel or what plist file I need to nuke to keep this channel from sending notifications?