: Open BDU and format your USB drive. This creates two partitions: an EFI partition (for OpenCore) and an HFS+ partition (for macOS resources).
Avoid "one-click" installers. Use the official Dortania Guide and build your EFI manually. It takes longer, but it guarantees your system works and is safe.
Some users utilize a combination of tools like gibMacOS to download the full installer files and then manually partition the USB drive into FAT32 for the EFI and HFS+ for the installer data.