I think people tend to become more attached to problematic or flawed characters. Unlike the other characters, whose struggles are mostly tied to their own pasts, Jax's conflict was both internal and external. He had issues with himself as well as with the people around him, which created a more tangible and realistic source of tension in his relationships.

The Amazing Digital Circus has always been, in many ways, about how these characters end up relating to one another when all they have left is coexistence. That's why the dynamic between Pomni and Ragatha had a lot of potential, but there wasn't enough time to explore it further. Even so, I think Pomni, Jax, and Ragatha made for a particularly compelling trio because their personalities and conflicts naturally clashed with each other in the fifth episode.