The data might be not syncing on iOS when you didn’t provide required permissions to Bayzat to read the data from Apple Health app.
Make sure that Apple Health app is recording your activity: Health app >> Show All Health Data
Check if you allowed Bayzat to read required data: Settings >> Health >> Data Access & Devices >> Bayzat >> Turn On All
If all data points are enabled, try to Turn Off All and then Turn On All