The Reminders app on my iPhone is completely blank

Hello,

The Reminders app on my phone is completely blank and I cannot add a reminder or see the existing ones in the main screen. The "Search" input in the Reminders App still works and I can see the upcoming or completed reminders if I search for them. Also, the Reminders widget still shows (only) the first seven due reminders. I can mark reminders as completed from a Search or from the widget.

In the Calendar App, if I hit "+" then "Reminder", the screen is also blank.

Screenshots:

• Blank Reminders app: https://i.ibb.co/r2h3DzCb/Reminders-App.png
• Search in the Reminders app (redacted for privacy): https://i.ibb.co/5WXyJPVb/Search-Reminders.png
• In the Calendar App trying to add a reminder: https://i.ibb.co/S7fL5wy4/Calendar.png

What I've tried:

• Marking some reminders as completed
• Modifying some existing reminders
• Shutdown and restart the phone
• Force restart with Volume+ Volume- and Power
• Uninstall the Reminders App and download it again from the App Store
• Restore the phone from iTunes (on Windows) and load a manual backup

I don't want to restore the phone as a new phone as I don't want to loose all the data.

I have an iPhone SE (2020) running iOS 18.5.

Can you help me please?

[Re-Titled by Moderator]