its not that bix and cassian’s relationship had no build-up, its that there’s no build-up to bix being a mother = a good ending for her.
the ending is presented as being as happy of an ending that she could hope for, but there’s no buildup to show that she would’ve wanted that ending. had the show included a scene of bix and cassian’s expressing want for a family after the war and/or her expressing a want in having children and/or being a maternal figure in someone else’s life, the problem here would be fixed, but it doesn’t.
a lot of people have compared bix’s ending to hera’s position in the rebels epilogue. for hera, being a mother makes sense given her character arc: the ghost crew’s structure was that of a family, where she gladly took on the position of mother with sabine and ezra, so an ending of her being a mother is in line with her character arc.
as much as i loved andor, i don’t think that bix’s arc in season two was handled particularly well. she does a lot of sitting around and waiting for cassian. other than killing dr. gorst, she’s not super active.
arc 1: wait for cassian, almost be raped
arc 2: sit on coruscant, have a drug addiction, wait for cassian to get back from ghorman
arc 3: sit on yavin and then leave
her choice to leave yavin wouldn’t have been diminished had she not been pregnant. a huge theme of this show is the sacrifices that people make for rebellion, and her sacrificing her relationship with cassian for the rebellion is a completed character arc that falls in line with the growth she’s given before.
At the end of the show, she’s given the position of the character that gets to see the peace that is to come. She gets to reap the benefits of the sacrifices of the rebellion. Its supposed to be presented as a happy peaceful moment, but we’re not given any reasons prior to the scene that being a mother and returning to the planet where she was violently assaulted is what she wants.
its not that there’s no build-up to cas and bix’s relationship, that’s not what the post is talking about, it’s no build-up to being a mother being a good happy ending for her.