If you wanna change your gender in your Wizz account, you have to:
👉 Go to your Profile (tap your picture on the top-left corner)
👉 Go to your Settings (tap the wheel on the top-right corner)
👉 Look for "My Data" and tap "Update my data" like on the screenshots below 👇
Click on "update" to send an update request. Once you fill the form, your gender will be updated 😀