To me, through episode 3, season 5 seems to be spun around the themes of fate and consequences. How when we're young, the stories we hear, intuit and make up about our families inform the people we become. How, as human beings, we can almost willfully ignore the signs of impending disaster, then haplessly lament or course-correct after the fact.
In Joanie's timeline, we see what the show projects as the consequences of heedlessness. There's nothing nifty about needing to grow strawberries indoors, or having your toilet test and spell out the results of your sample, every time. Nothing cool about hating the very idea of making your own children. But here we are, says the show, because of what we did and didn't do, decades before. Because the only one thing we knew how to do was to be the way that we are, and then, sink back into the ocean.
So it wasn't just Alison. And back in the last century, it also wasn't only Alison who was forced to make up her own mind about who and where she came from. Alison was told that her father could be anyone, by the mother who disappeared and re-appeared under a new name. But Cole's father disappeared, re-appeared, then committed suicide "out of the blue," leaving behind a family and the family ranch. Noah's mother was mortally ill throughout his adolescence and finally asked him to help her commit suicide, so that they both could escape. Helen had it lot easier in many ways, hindered mostly by two parents off serving on the front lines of a permanent war with one another.
Ten years ago, Noah and Alison had an affair that "ended" two marriages and one family, leading to two other marriages and one re-made family, as well as Joanie Stormborn. Joanie, whose mother gave birth to her alone in a nor'easter like the night she died; fathered first by Noah and then by Cole, mothered by Alison, then Luisa, then both, then...? Joanie, who has good reason to believe that her elders did her wrong: that her father's father was a runaway who came back to kill himself; that her mother's mother was a runaway who came back to leave again; that her mother let her first child drown, left Joanie's father, and left Joanie to go drown herself.
Meanwhile, to Joanie, their legacy is a whole world created by what happens when people don't take care of what matters most. She may scorn her elders for calling the consequences "fate," but that's also what her heart narrates about the undertow within her. She just thinks of it as neurochemistry, and not the gods' caprice.