I came to this thread a bit too late, but if you're interested in the actual signal that Stella found, take a look at the spectrum vs time on the NASA release [1] - third plot on the page, with a convenient slider that lets you flip back and forth to see the previously known plasma oscillation events and the newly discovered continuous signal. Notice the huge change in scale!
[1] https://www.nasa.gov/feature/goddard/2021/as-nasa-s-voyager-...