Our system is existed and upgrading into EF Core

We have an EntityBase class for all entities to inheritance, but every derived class has its own key "Sid"

EntityBase.cs

public abstract class EntityBase
{
    // some other properties
    public UpdateInfo UpdateInfo { get; set;}
}

UpdateInfo.cs

public class UpdateInfo
{
    // some other properties
    public string CreatedBy;
}

All business entities class is like

public class BusinessEntity: EntityBase
{
    // some own properties
}

Now in our original database, every UpdateInfo will map to the derived class table as "UpdateInfo_CreatedBy" using EF 6 ComplexType with column constraint. Table will be like:

table structure

But I don't know how to map to the original database with EF Core fluent API in "OnModelCreating" with bulk configuration without changing the original database table structure and original business class definition.

EDIT:

I finally found out how bulk configuration works and successfully made the UpdateInfo normally Add-Migration