Very late to the game here, but one way to force discovery of new music is to use the "I'm tired of this song" feature. On the Now Playing page, below the image of the album, are three dots. Click on them, and one of the options is "I'm tired of this song". Click on it, and (for this channel? for all channels?), the song will be taken out of circulation for a month. Do that on enough songs, and the engine is forced to find new music for you. But then there's no way to undo this, except to wait a month.
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