Is it possible to hide or delete the link: PRE-BUILD WEBSITES? (from the admin too)
Yes, you can hide it by unchecking this feature in Betheme -> Theme options -> Global -> Advanced.
Thanks for answering me.
There is no way to permanently delete this item so even the administrators do not see it
If you turn it off there, then the Pre-built websites tab will not be visible, but in advanced options, will still be an option to turn it on again.
But, you can turn off the Advanced tab from theme options with the BeCustom plugin.