The first book in any series is always great, The author has had ample time to plan and work on their draft, which always shines in the resulting production. The second book, by contrast, can be where things fall apart.
Not here.
While the plot of Carl’s Doomsday Device is still silly and cobbled together from your favorite tropes, the emotional impact of the characters and the wider story arcs are growing on me, The voice work, as always, is perfect. After this book, I can say with certainty that I will be listening to the whole series.