Use the Chrome Browser Extension to upload your data from Garmin Connect to garminbadges.com
No need to input your Garmin Connect credentials and it works with 2FA (two factor authentication).
On Android phones you can use
Kiwi Browser to run the Chrome extension.
Download from Chrome Web Store
Note that the function below does NOT work if two factor authentication is enabled. Use the browser extension instead.
Submit your data here to use it in the front page.
After you have added your badges find your username in the Username dropdown.