Microsoft does not host standalone, official direct links to individual .msi files like windows pe boot files -onecoreuap--x86-en-us.msi . Downloading standalone MSIs from third-party hosting sites poses significant security risks, including malware infection and compromised binaries.
"The installer encountered an error 0x80070643"
from devices that cannot boot into the full OS. Modify an offline Windows installation. Why the specific MSI?