https://www.bleepingcomputer.com/news/microsoft/how-to-manually-install-windows-10-cumulative-updates/

For most people, Windows updates are installed automatically with little to no efforts by users. In some cases, though, Windows 10 may fail to download and install the cumulative updates (monthly updates) or Windows Defender virus definitions.

If you are experiencing issues with Windows Update or you have multiple PCs, you might want to use the Windows Update Catalog to download and install Windows updates manually.