SwaggerUI custom ValidationAttribute not working on client's validation in Asp.Net Web API

Question

Problem: I wrote derived class from DataAnnotation.StringLengthAttribute attribute that allows exact number of characters instead of Min/Max.

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My string: enter image description here

How can I override this default message for ErrorMessage?

Then I've tried to change ErrorMessage property, but it doesn't appers if string is invalid. Just default message appears only.

    /// <summary>
    /// Specifies the exact length of characters that are allowed in a data field.
    /// </summary>
    public class ExactStringLengthAttribute : StringLengthAttribute
    {
        public ExactStringLengthAttribute(int length) : base(length)
        {
            //ErrorMessageResourceName = nameof(ValidationMessages.ExactStringLength);
            //ErrorMessageResourceType = typeof(ValidationMessages);

            ErrorMessage = nameof(ValidationMessages.ExactStringLength);

            MinimumLength = length;
        }
    }

I've tried to inherit from ValidationAttribute instead of StringLengthAttribute, but in this case there is no message at all. (It's the second question.)

/// <summary>
/// Specifies the exact length of characters that are allowed in a data field.
/// </summary>
[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter,
AllowMultiple = false)]
public class ExactStringLengthAttribute : ValidationAttribute
{
    public ExactStringLengthAttribute(int length) : base(() => ValidationMessages.ExactStringLength)
    {
        //ErrorMessageResourceName = nameof(ValidationMessages.ExactStringLength);
        //ErrorMessageResourceType = typeof(ValidationMessages);

        //ErrorMessage = nameof(ValidationMessages.ExactStringLength);

        Length = length;
    }

    /// <summary>
    ///     Gets the maximum acceptable length of the string
    /// </summary>
    public int Length { get; }

    /// <summary>
    ///     Override of <see cref="ValidationAttribute.IsValid(object)" />
    /// </summary>
    /// <remarks>
    ///     This method returns <c>true</c> if the <paramref name="value" /> is null.
    ///     It is assumed the <see cref="RequiredAttribute" /> is used if the value may not be null.
    /// </remarks>
    /// <param name="value">The value to test.</param>
    /// <returns><c>true</c> if the value is null or less than or equal to the set maximum length</returns>
    /// <exception cref="InvalidOperationException"> is thrown if the current attribute is ill-formed.</exception>
    public override bool IsValid(object? value)
    {
        // Check the lengths for legality
        EnsureLegalLengths();

        // Automatically pass if value is null. RequiredAttribute should be used to assert a value is not null.
        // We expect a cast exception if a non-string was passed in.
        if (value == null)
        {
            return true;
        }

        int length = ((string)value).Length;
        return length == Length;
    }

    /// <summary>
    ///     Override of <see cref="ValidationAttribute.FormatErrorMessage" />
    /// </summary>
    /// <param name="name">The name to include in the formatted string</param>
    /// <returns>A localized string to describe the maximum acceptable length</returns>
    /// <exception cref="InvalidOperationException"> is thrown if the current attribute is ill-formed.</exception>
    public override string FormatErrorMessage(string name)
    {
        EnsureLegalLengths();

        // it's ok to pass in the minLength even for the error message without a {2} param since string.Format will just
        // ignore extra arguments
        return string.Format(CultureInfo.CurrentCulture, ErrorMessageString, name, Length);
    }

    /// <summary>
    ///     Checks that MinimumLength and MaximumLength have legal values.  Throws InvalidOperationException if not.
    /// </summary>
    private void EnsureLegalLengths()
    {
        if (Length < 0)
        {
            throw new InvalidOperationException("");
        }
    }
}

Possibly similar thread: https://github.com/dotnet/aspnetcore/issues/4848?ysclid=lrun12evt921520779

I didn't find any information about client's validation in Swagger UI and how can I configure it.