One of the open assessment points out that "The Scrum team should develop and deliver at least one piece of functionality in the first Sprint".
1) The new Scrum Guide (Nov 2020) is not as prescriptive and does not point out the need for atleast one functionality to be developed in a Sprint.
2) With the New Scrum Guide, end of the Sprint the increment should be valuable. End of the Sprint, I could have an increment which could have no functionalities added, however it could be more valuable at the end of the Sprint. (E.g. Code refactored, improved performance etc)