Songs of Conquest was announced the same year Netflix's The Witcher came out, and they might have been inspired by the viral "toss a coin to your witcher" song, which would explain the bard song segments between each campaign mission.
Songs of Silence is heavily based around the Lord of the Rings idea that the world is created by a divine song, and evil is caused by dissonance in the song. People and animals who lose their connection with the song turn into undead things. The main conflict driving the story is a crusade of zealots consuming the world with the nothing the silence to end the corrupted song and rebirth the world with a fresh and harmonious song.