Best way to upgrade from Catalina to Big Sur?

Hello again!

I was doing a small research on the dortania docs for a path to upgrade my exiting hackintosh from Catalina to Big Sur and ended here: https://dortania.github.io/OpenCore-Install-Guide/extras/big-sur/#table-of-contents but I don't quite get it,

So, do you know the best way to upgrade from Catalina to Big Sur without having to reinstall the OS again and all my files?