I have screen 1 where the usernames of the users are saved. The second screen can display the persons username but the third screen does not show the username. I used the same coding as screen 2.
you don't need to pass like "start value" the data stored in tinyDB. Data stored in tinyDB can be accessed from any screen, using the same namespace and the same tag name. so, make sure you are using the same namespace in all the screens (and the same tag).