https://www.bleepingcomputer.com/news/microsoft/how-to-uninstall-and-downgrade-windows-10-20h2-to-previous-versions/

If you are running into issues with Windows 10 20H2, otherwise known as the October 2020 Update, this guide will explain how to roll back to your previous version of the operating system.

When upgrading to the Windows 10 20H2 feature update, one of two methods will be used depending on what version of Windows 10 is being upgraded.