I think one of the biggest issues with BE attempting to follow in AC’s footsteps is that the factions were not distinct, and it felt extremely generic. BE’s factions were all similar, played similarly, and all had the same options for development and could all take the same evolutions. In AC, not only were the faction leaders ideologies revealed in quotes in the tech tree and secret projects, it was inescapable in the game mechanics. The reason I feel Stellaris is a closer sibling is that it managed to mimic something of how it felt to be an idealogical leader attempting to make sure your values and your goals for the future were the ones that were supreme. BE was “civ in space”.
Yes, the first one is goofy but it did the whole “what would an actually average person do with superhero powers” shtick before it was cool, and managed to make it funny and pretty sweet too.