Hi there,
As you mentioned above, you already tried to perform the suggested steps from the previous support and the same issue persists. In this case, we actually need to check and isolate the main issue if this has something to do with the device, with the iCloud
sync settings, or with the account itself. We may need to perform some troubleshooting steps here and see if this helps or make any changes:
Step 1: Restart the Contacts, Calendar, or Reminders app.
- Double-click the Home button to see your open apps.
- Find the app, then swipe up to close it.
- Press the Home button to return to your Home screen.
- Wait a minute, then open the app again.
Step 2: Turn off iCloud Contacts, Calendar, or Reminders and turn it back on.
- Tap Settings > [your name] > iCloud. (If you're using iOS 10.2 or earlier, go to Settings > iCloud.)
- Slide to turn off Contacts, Calendars, and Reminders.
- If you see your calendars or reminders on iCloud.com or any of your devices, you can choose Delete from My [device]. If not, choose Keep on My [device].
- Wait a few minutes, then turn on Contacts, Calendar, or Reminders again.
Step 3: Restart your device.
Let us know if this will help address your concern.