Definitely not. These types of stories usually lack any real literary merit. They are more about titillating the reader with sexual details rather than providing any kind of profound insight. Good literature should be about exploring the human condition, society, and culture, not just about sexual fantasies. And such stories can also be offensive to many people, so they have no place in proper modern literature.
The plot involves Rimuru's journey from being a rather weak (initially) slime to becoming a very powerful being. He meets many interesting characters. For example, there are the goblins he befriends early on. Rimuru helps them improve their living conditions. As the story progresses, he also has to deal with the threat of other more powerful monsters and even some human kingdoms that view his growing power with suspicion. In general, it's a story full of adventure, growth, and the forging of relationships in a magical and dangerous world.
I'm not sure who this 'Douglas Smith' specifically is in relation to such inappropriate stories. There could be many people named Douglas Smith, and it's not ethical to promote or be associated with 'sex smut' content.
The main character is Rimuru Tempest. He is a slime who has unique powers and a great deal of charisma. Another important character is Veldora, the storm dragon who befriends Rimuru. There is also Shizu, a human who has an impact on Rimuru's early development. And then there are characters like Benimaru, a powerful ogre who becomes one of Rimuru's loyal followers.