Suggestions to rollback Windows 10 to older version

Hello All,

I would like to know the steps to rollback windows 10 to an older version of Windows 10.

Example : 2004 or 20H2 to 1903 or 1909 (To the version of windows before upgrade)

I understand that we can extend the 10 day limit by specifying the value up to 60 days with the command DISM /Set-OSUninstallWindow. 

DISM /Initiate-OSUninstall has the ability to revert the PC to a previous version. However, I strongly believe, someone in the IT community would have a better way to deal with the reverting of the upgrade to a previously installed Major upgrade version.

I am trying to know if there are any other workarounds with the way the OS is deployed like, Upgrade Task Sequence and Feature Update installation?

Can we copy the Windows.old folder to the machine which has to be reverted, if so, do we need to set any other registry values or modify any other files?