Umarufag here. Since practically nobody on /a/ has gotten past episode one Let Me Tell You About why Umaru Doma IS NOT the worst.
In season 1 she gets very little development and is of course just autistic neet gremlin.
BUT IN SEASON 2. She actually gets a lot of development even in Gremlin mode, she learns that she doesn't have to hide who she is, that no matter how annoying or selfish you are THERE ARE people out there that love you and care about you. More importantly in her gremlin/imouto mode she learns to not be nearly as selfish or annoying and infact actually starts to be more responsible and overall a better character.
You want the actual worst character. Its Ebina. I don't fucking regret saying any of this.