It is not supposed to work for "http://localhost:8080/codeIgniter4/" - that's why the error message.
You need to set your "document root" to the public folder inside your project. <-- it told you this
Once fixed, you would access your project as "http://localhost:8080" or as "http://project.local:8080" if using a virtual host entry for "project.local" (which is my preference).
