What is the correct SharePoint web architecture?
Classic SharePoint architecture is typically built using a hierarchical system of site collections and sub-sites, with inherited navigation, permissions, and site designs. Once built, this structure can be inflexible and difficult to maintain. In the modern SharePoint experience, sub-sites are not recommended.
How secure is a SharePoint site?
While it is possible for a hacker to access such secured cloud storage, it is highly unlikely to occur. Both One Drive and SharePoint Online have multiple layers of security, so there are no one-shot means to sneak into storage.