Default Bluesky is mostly flowers and cats. Default X is mostly people getting hurt and dumbass macho advice lists.
If you show up to Bluesky without following anyone, you'll be treated to a series of posts about art, music, and dogs. If you show up to X without following anyone, you'll be bombarded with right-wing conspiracies and white supremacist slop. It's weird which one is seen as a "political bubble"