Custom hyperlinks in Richtextbox WINFORMS control

I am designing a word processor, my main mission is to emulate the functionality of a IntelliSensebut used for another purpose. To compose it I use a control Datagridviewand a Richtextbox.

The pseudointellisense function appears when I open a bracket ( '[' ) and ends if I click on some of the filtered data in the datagridview or if I close the bracket ( ']' ). What I need is to create a hyperlink once I click on one of the options that are shown to me and when I make a key to a function.

What is the problem with all this?. The control richtextboxhas keywords to create links but these only work if the content is formatted as a link such as ...

And what I need to do is something like this

To be able to enter the text that I want and that is a hyperlink

Then I found the control's own RTF language (Rich Text Format). I didn't know it and from what I read it works like a kind of HTML. When trying to implement it, I don't end up using part of myself either because I lack knowledge of its use and because of the way I have coded the program.

Function that is called when writing on the Richtextbox

private void textBox1_TextChanged(object sender, EventArgs e)
    {
        if (verificarDeCorchete)
        {
            char[] corchetes = new char[] { '[', ']' };
            string where_buscador = VALOR_WHERE.TrimStart(corchetes);
            textBox3.Text = where_buscador;

            dt_gv.DataSource = connections.conn_database.SELECT($"SELECT * FROM tabla_de_nombres WHERE Descripcion LIKE '{textBox3.Text}%'");
            if (dt_gv.Rows.Count > 0)
            {
                //Muestra el intellicense
                dt_gv.Visible = true;

                //Este codigo sirve para seguirle el rastro al carrete y 
                //asi el intellicense este donde se pueda ver
                var o = Utility.GetCaretPoint(richTextBox1);
                xpos = o.X;
                ypos = o.Y;
                textBox2.Text = Convert.ToString(xpos + "," + ypos);
                dt_gv.BringToFront();
                dt_gv.Location = new Point(xpos + 15, ypos + 30);
                richTextBox1.Focus();

            }
            else
            {
                dt_gv.Visible = false;
            }
        }
    }       

Function that validates which character is being entered (to know when it is opening and closing brackets)

 private void richTextBox1_KeyPress(object sender, KeyPressEventArgs e)
        {
            //Si es inicio de corchete activa el boleano
            if (e.KeyChar.ToString() == "[")
            {
                verificarDeCorchete = true;
            }
            //Si es el final de corchete lo desactiva
            else if (e.KeyChar.ToString() == "]")
            {
                verificarDeCorchete = false;
            }

            //Si el boleano esta activado o es el final de un corchete entra al if
            //Se agrego la condicion del corchete cerrado para que lo pinte de rojo tambien.
            if (verificarDeCorchete || e.KeyChar.ToString() == "]")
            {
                //Desactiva la vista del "Intellicense"
                dt_gv.Visible = false;

                //Pinta de rojo los colores dentro
                richTextBox1.SelectionColor = Color.Red;

                /*Si el valor del string es nulo agrega el caracter 
                 * (esto pasa solo si es el primer caracter)*/
                if (VALOR_WHERE == null)
                {
                    VALOR_WHERE = e.KeyChar.ToString();
                }
                else
                {
                    //Si el string es distinto a 0
                    if (VALOR_WHERE.Length != 0)
                    {
                        /*Esta condicion sirve para los backspace
                         al tocar esta tecla el programa lo leia como un caracter
                         (aunque no lo fuera) y rompia la logica y dejaba un string
                         mal escrito. Al hacer esto se borra el caracter (como pasa exactamente)*/
                        if (e.KeyChar.ToString() == "\b")
                        {
                            VALOR_WHERE = VALOR_WHERE.Remove(VALOR_WHERE.Length - 1);
                        }
                        else
                        {
                            VALOR_WHERE = VALOR_WHERE.Replace(VALOR_WHERE, VALOR_WHERE + e.KeyChar);
                        }
                    }
                    else
                    {
                        //Si es 0 copia el valor como pasa cuando es nulo.
                        VALOR_WHERE = e.KeyChar.ToString();
                    }
                }
                //Copia el valor en el textbox para pruebas. esto tiene que borrarse.
                textBox1.Text = VALOR_WHERE;
            }
            else
            {
                //Cambia el color de la fuente si no es una busqueda especial.
                richTextBox1.SelectionColor = Color.Black;
                //Lo lleva a vacio para volver a usarse en otro momento.-
                VALOR_WHERE = "";
            }
        }

With this function when clicking on any of the datagridview options it pastes it in the richtextbox. In this part the code that creates the link should be implemented. (In hyperlink I need it to call a function, not to enter a web page.)

 private void dt_gv_CellClick(object sender, DataGridViewCellEventArgs e)
    {
        dt_gv.Visible = false;
        verificarDeCorchete = false;
        //Obtiene la posicion del carrete en ese momento
        int caret_position = richTextBox1.GetCharIndexFromPosition(Utility.GetCaretPoint(richTextBox1));
        int start_index = caret_position - VALOR_WHERE.Length;
        int length = VALOR_WHERE.Length;

        richTextBox1.Text = richTextBox1.Text.Remove(start_index, length);

        string valor_seleccionado = dt_gv.CurrentCell.Value.ToString();

        richTextBox1.Text = richTextBox1.Text.Insert(start_index, " " + valor_seleccionado + " ");

        richTextBox1.Text = richTextBox1.Text.Replace("[", "");
        richTextBox1.Text = richTextBox1.Text.Replace("]", "");

        richTextBox1.SelectionStart = start_index + length + valor_seleccionado.Length;
    }

When opening brackets

When clicking on some option (This should be a hyperlink)

Any ideas?