Especially since having a second child start growing up, I've realized it's actualy four stories, often all compelling at once. There's Bluey's story, and there is the dad's and mom's story, but there is also Bingo's story, about being the younger child. My younger kid loves the episode called "Bingo", which is specifically about Bingo.
There's another Bingo-focused episode, called "BBQ", that's absolute favorite of my little Bingo's. My younger daughter (3.5yo now) definitely sees herself in the Bingo character.