"Your device is missing important security and quality fixes."
Is that what you see on your Windows Update on your Windows 10 machine? And no matter how many times you click, it will return the same and find no update.
I was getting frustrated with that warning message on my new Microsoft Surface Go, after 7 years not using any Windows OS machine. My last used OS was Windows 7.
Using my 7 years ago knowledge of Windows, I bet Microsoft never change. So did a restart and still didn't help. So decide to google for it since it could be a bug and a separate patch is required.
Not surprising this was still true after 7 years. Following the guide here, I downloaded the Windows 10 October 2018 Update to move up another level of Windows 10 Build 1809.