The "To Do" at the top is throwing me. I don't have that in any of the views in my Reminders app, so far as I can tell. I'm using iOS 18.4.1 on a 16 Pro.
Anyway, have you tried different views. For example, I would select "All" and see what you see. The way I understand it, you should see every reminder, in all accounts, in all lists.
Next step would be restart the device.