If you don't intend to uninstall the installed patch, or you don't intend to install it again after uninstalling, you can delete it. System patch backup, just in case, convenient for users.

As for the suggestion that one patch was replaced by another patch, it is because Microsoft replaced the previous patch with a new patch, so just install the new patch directly.

Generally speaking,no. If you patch with Guard, the patch installation file will keep the default settings.