fluent api. How to disable TPH? Why is EF trying to find a field that doesn't exist in the entity?

Question

Entity Framework

Help. How to disable TPH, or rather, so that EF does not require the creation of the Discriminator field? And can you explain why FE is looking for a field (in my case it is supplier_Id) that does not exist in the entity?
Essence

public class Supplier
    {
        public int Id { get; set; }
        public int companyId { get; set; }
        public virtual Company Company { get; set; }
}

Configuration

public class SupplierConfiguration : EntityTypeConfiguration<Supplier>
    {
        public SupplierConfiguration()
        {
            ToTable("suppliers");
            HasKey<int>(s => s.Id);
            Property(s => s.companyId).HasColumnName("companyid").IsRequired();
            HasRequired(s => s.Company).WithMany().HasForeignKey(s => s.companyId);
        }
    }

Context

protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
            modelBuilder.Configurations.Add(new SupplierConfiguration());
            modelBuilder.Configurations.Add(new CompanyConfiguration());
            modelBuilder.Configurations.Add(new CountryConfiguration());
            base.OnModelCreating(modelBuilder);
        }

Thanks in advance =)