How to install Windows Admin Center (WAC) in an unattended mode using a self-signed certificate

You can choose to remove the log switch as shown below.

msiexec /i WindowsAdminCenter1910.msi /qn /L*v c:MsiExec-output.txt SME_PORT=443 SSL_CERTIFICATE_OPTION=generate

See the following link to get a full understanding of what the syntax (commands) above does https://www.klaus-hartnegg.de/gpo/msiexec.html

SSL certificate usage, run the following command to install the Windows Admin Center with an existing certificate

msiexec /i <WindowsAdminCenterInstallerName>.msi /qn /L*v log.txt SME_PORT=<port> SME_THUMBPRINT=<thumbprint> SSL_CERTIFICATE_OPTION=installed