Because Windows 10X was never officially released to the public, there is no "official" retail ISO. The versions found on Internet Archive are typically leaks or builds extracted from Microsoft’s emulator. Popular entries often searched for include: 19041.2251 PROFESSIONAL X 64 EN US (Windows 10X)
Instead of hunting raw ISOs on archive.org, look for (often uploaded to archive.org or Windows enthusiast forums like BetaArchive). These have the bootloader fixed and require no conversion. windows 10x iso archive.org