1
Create profile screen for onboarding where users enter a display name (optional) and choose a username, with text input fields and a Save action in the top bar to submit profile details.
2
Create profile screen for onboarding that lets users enter an optional display name and choose a username/handle in text fields with clear icons and a clear-input control. A prominent Save button in the header submits the profile details.
3
Profile setup/edit screen for entering a display name (optional) and choosing a username with an @ handle, including inline validation error messaging that the username is already registered and a disabled Save action until a valid unique username is provided.