As I said, implementing a whole bunch of features and overhauling the framework, so the features offered are clicking together and have a robust concept and ecosystem around them.
Since this is not gonna happen any time soon, as a web game developer, just ask the user for their name for that leaderboard. And if your game is bigger, you would have your own servers that would help with logging in users and no need for an underlying framework that Itch would provide.