✅ How to save to database with ISO format?

public class Entity
{
    public required Guid Id { get; set; }

    public LocalDateTime CreatedAt { get; protected set; }
    
    public DateTimeZone CreatedAtTz { get; protected set; }

    protected Entity()
    {
        Id = Guid.NewGuid();
        CreatedAt = LocalDateTime.FromDateTime(DateTime.UtcNow);
        CreatedAtTz = SystemClock.Instance.GetTimeZone();
    }
}

public static class DateTimeExtensions
{
    public static DateTimeZone GetTimeZone(this SystemClock systemClock)
    {
        var instance = systemClock.GetCurrentInstant();
        var zone = DateTimeZoneProviders.Bcl.GetSystemDefault();
        
        return instance.InZone(zone).Zone;
    }
}