When you navigate to Sites>Blogs and have your new "Default Blog Website" There needs to be an option when the 3 dots are clicked to Edit for the slugs, meta description, and Title. Everything you input in a new blog site should also have the option to be able to edit later on. Currently, there is no way to edit any of that information.
Creating a new blog site is out of the question because all of my social posts and anything else i have used the blog link for has the "Default Blog Website" URL. It is much easier to edit the information on the "Default Blog Website" then it is to change all of the backend URLs.