Thanks very much for the follow up, Sarah!!
The Zwift app shouldn’t be used for editing workouts at all. It should just be used to run them. Editing a workout on a tiny phone screen or Apple TV is just a bad user experience. Zwift is aware of the issues but is either unable or unwilling to fix them.
The best solution to all these issues with Custom Workouts is for Zwift to provide a web-based version of the Workout Editor now built into the Zwift app. It would operate directly on a user’s Custom Workouts in the ZwiftCloudFromHELL - the SINGULAR place Custom Workouts should be kept and managed (other than your own backup copy of course - you know, for when the next “upgrade” “fixes” something)…
Once yo create a custom workout on one device, you need to close the Zwift app & then reopen it on that same device. If you don’t, the new workout will not appear on other devices/