如何使用IEquatable找到两个对象之间的差异？

问：

我通过在对象上实现 IEquatable 接口来比较两个相同的对象。如果它们不相等，则更新数据库;否则，请保持原样。这里的上下文是，我需要使用来自 excel 工作表的数据更新表格，并比较数据并仅在数据发生更改时更新。

下面是相同的代码

var constructionMaterialTypes = package.GetObjectsFromSheet<ConstructionMaterialTypeExcelDto>(ConstructionDataSheetNames.CONSTRUCTION_MATERIAL_TYPE,
                                                                                              ConstructionDataTableNames.ConstructionMaterialType);
var materialTypes = new List<ConstructionMaterialType>();
foreach (var materialType in constructionMaterialTypes)
{
    var materialTypeId = GetGuidFromMD5Hash(materialType.name);
    List<string> materialTypeNotes = new();

    if (!string.IsNullOrEmpty(materialType.notes))
    {
        materialTypeNotes.Add(materialType.notes);
    }

    var existingMaterialType = ctx.ConstructionMaterialTypes.SingleOrDefault(cm => cm.Id == materialTypeId);

    var constructionMaterialType = new ConstructionMaterialType
    {
        Id = materialTypeId,
        Name = materialType.name,
        NotesHTML = materialTypeNotes
    };

    if (existingMaterialType != default)
    {
        if (existingMaterialType != constructionMaterialType) // Object comparison happening here 
        {
            existingMaterialType.Name = materialType.name;
            existingMaterialType.NotesHTML = materialTypeNotes;
        }
    }
    else
    {                       
        materialTypes.Add(constructionMaterialType);                       
    }
}

然后下面是我实现 Iequatable 接口的实际类

public sealed class ConstructionMaterialType : IIdentity<Guid>, IEquatable<ConstructionMaterialType>
{
    [Key]
    public Guid Id { get; set; }
    public string Name { get; set; }
    public List<string> NotesHTML { get; set; }
    public bool Equals(ConstructionMaterialType other)
    {
        if (other is null)
            return false;

        return this.Id == other.Id
            && this.Name == other.Name
            && this.NotesHTML == other.NotesHTML;
    }
    public override bool Equals(object obj) => Equals(obj as ConstructionMaterialType);
    public override int GetHashCode()
    {
        int hash = 19;
        hash = hash * 31 + (Id == default ? 0 : Id.GetHashCode());
        hash = hash * 31 + (Name == null ? 0 : Name.GetHashCode(StringComparison.OrdinalIgnoreCase));
        hash = hash * 31 + (NotesHTML == null ? 0 : NotesHTML.GetHashCode());
        return hash;
    }
}

即使两个对象都持有相同的值，此条件也始终为真，并且我还附加了图像以供参考existingMaterialType != constructionMaterialType

我不确定我在上面的代码中哪里做错了。谁能为我指出正确的方向？ 提前非常感谢