Using ei.cfg with Windows 10/11 ISO using any plugin.

[nguyen ha thai trong]

You don't need an ei.cfg.
Just use an  XML file which has a blank <Key></Key> entry or specify a generic install key (e.g. for W269N-WFGWX-YVC9B-4J6C9-T83GX Win10 Pro).

Code:

<?xml version="1.0" encoding="utf-8" ?>
<unattend xmlns="urn:schemas-microsoft-com:unattend">
<settings pass="windowsPE">
<component name="Microsoft-Windows-Setup" processorArchitecture="x86" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<UserData>
<AcceptEula>true</AcceptEula>
<ProductKey>
<Key></Key>
</ProductKey>
</UserData>
</component>
<component name="Microsoft-Windows-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<UserData>
<AcceptEula>true</AcceptEula>
<ProductKey>
<Key></Key>
</ProductKey>
</UserData>
</component>
</settings>
</unattend>

Are you using Ventoy Auto Installation Plugin?