The reason they’ve been showing all Zeb and no Kallus is cause Zeb has mostly healed from his trauma on Lasan. He’s able to go on independent missions and fight while not looking back (as much) cause he’s made his peace. He may think about the people he lost but ever since season ONE of rebels his healing has been relatively constant and even when it gets bad again he had his family to help pick him back up.
Kallus, however, can never forget. Not only did he actively participate in the slaughter of Zeb’s people (influenced by the Empire yes but he still acted on it), but he also proceeded to hold up the empire for years as one of their BEST. He held that title with pride and never looked back until Zeb’s kindness rerouted his brain away from the Imperial “do what the higher ups tell you they are always right” shit. Now, ever since the war ended, his life is and will always be dedicated to saving what little that he can from what he stole from the universe. He writes books, most likely helps out his community on Lira San, ect.
Zeb is dedicated to the rebellion. His people are still a part of his life but so is the rebellion. He doesn’t have to reference any personal matters because he’s very good at emotionally regulating especially after living with Jedi all his life. Kallus is tied to his wrongdoings. It’s not a good or bad thing it’s a simple fact. Rebels will see he was part of the empire, he will always be focused on his part in restoring what was lost. He can’t be mentioned out of context of Zeb’s people and that’s a sharp slope to Zeb himself cause of his influence over his life.
Disneys too scared to show their very obviously romantic relationship simple as that. So they choose the easy route and just show Zeb and put him to work.
