If you are concerned about legality, create your own vanilla USB installer using the createinstallmedia command and then manually add Olarila’s EFI folder. The RAW image is primarily a convenience tool.
Version 11.2 was a stable milestone in the Big Sur lifecycle, often favored for its compatibility with various kexts (drivers) before Apple introduced more restrictive changes in later point releases. Olarila Vanilla Images - macOS Installer olarila big sur 11.2.raw download