MultipleErrorStrings.cs

public void Create(string name, string email, string billingInfo)
{
    Result<CustomerName> nameResult = CustomerName.Create(name);
    Result<Email> emailResult = Email.Create(email);
    Result<BillingInfo> billingInfoResult = BillingInfo.Create(billingInfo);
    
    return Result.Combine(nameResult, emailResult, billingInfoResult)
        .OnSuccess(() => _paymentGateway.ChargeCommission(billingInfoResult.Value));
    /* Other OnSuccess, OnFailure, OnBoth methods */
}

public class Result
{
    public bool Success { get; private set; }
    public string[] Errors { get; private set; }
    
    public static Result Combine(params Result[] results)
    {
        if (results.Any(r => r.Failure))
        {
            string[] errors = results.SelectMany(r => r.Errors).ToArray();
            return Fail(errors);
        }
 
        return Ok();
    }
    
    /* Other members as before */
}