If your ISO is over 4GB and you are using FAT32, WinSetupFromUSB will usually ask to split it. Always click Yes .
WinSetupFromUSB version 1.10, released on November 7, 2021 , marked a pivotal update for the long-running multiboot utility by officially introducing support for Windows 11
: Improved detection for higher Windows 10 build numbers to ensure boot menu names accurately reflect the version being installed. Large Disk Safety