Start11 will not import the Windows 10 menu right now.
This is something we are looking at for the future, but it would require Start10 to support folders in the Windows 10 style menu which isn't something we currently have. Once we do support those I would imagine we will import the current layout.
A clean install of Start11 on Windows11 however will import pinned items from the Windows 11 menu as there is no folder issue to worry about.
Anything you have set in Start11 prior to an upgrade to Win11 should not be impacted by an upgrade to Windows 11 as it is all stored in Stardock registry keys which the upgrade should not touch.