Several free, open-source Start Menu replacements exist. They are legal, safe, and actively maintained:

An excellent tool for Windows 11 users who want the Windows 10 taskbar and Start menu back without paying for a license.

StartIsBack is developed by a single person, and its licensing model has undergone changes over time. Initially, the tool was released with a free trial, and users could purchase a license key for continued use. However, some users have shared license keys on GitHub and other platforms, which has led to discussions about the legitimacy and safety of using patched or cracked versions.