If you’re stuck like me and get an internet dropout and Zwift is unable to successfully upload your workout even after regaining a connection. Look no further than using the iMazing mac app. After downloading the app you will be able to browse your iPad in my case to locate the .fit file then proceed to uploading to Garmin, Strava etc. Best of luck and ride on!
Update: Zwift on iPad now supports manually emailing .fit and log files.