Supprimez l'une des boucles :
for (int x = 0; x < dt.Rows.Count; x++)
{
Console.WriteLine(dt.Columns[0].ColumnName + " ");
Console.WriteLine(dt.Rows[x].ItemArray[0].ToString() + " ");
Console.WriteLine(dt.Columns[1].ColumnName + " ");
Console.WriteLine(dt.Rows[x].ItemArray[1].ToString() + " ");
Console.WriteLine(dt.Columns[4].ColumnName + " ");
Console.WriteLine(dt.Rows[x].ItemArray[4].ToString() + " ");
}
Ou
foreach (DataRow dr in dt.Rows){
Console.WriteLine($"{dr[0]} - {dr[1]} - {dr[4]}");
}