Litchi Pilot is the app you are asking for, and it’s android only - no SDK for iOS so we can’t do it for iOS. Also it’s only compatible with some drone models because the new DJI SDK is not compatible with all drone models: [OPEN BETA] Litchi Pilot
Regarding the loss of your saved DJI Fly flights, please contact support@flylitchi.com with details about your setup so we can investigate further. It may be caused by a bug in Litchi Hub Bridge. It does already try to backup your flight database and restore it when transfer issues happen but we’re still early in development and there may be bugs.