To be honest... Diligence isn’t really Rubel’s forte. Anything that is considered consistent and hardworking, really.
First, they’re a sloth bun. Not to prey on stereotypes, but Rubel themself knew that their vice must count for why they can barely stay awake longer than others. They can’t keep up any hobby for more than a week, and even then they lose interest in anything quickly. Why did they think taking up tasks at the Heavenly Embassy seemed like a good idea?
Second...