JavaScript button press emulation

In C#, the Chromium browser is installed, and it is required that when clicking the button in the program, the text field becomes active. The website used is - https://chat.deepseek.com/ - here it is necessary for the program to insert a message into the text field and send it. The code used only inserts the message into the text field, but it remains inactive until any key on the keyboard is pressed manually, meaning an emulation of pressing the enter or space key is needed.

The code that previously worked and correctly sent messages: 

            string script = "var input = document.querySelector('#chat-input');" +

$@"input.value = '{textBox1.Text}';" +

"var event = new Event('input', { bubbles: true });" +

"input.dispatchEvent(event);";

            browser.ExecuteScriptAsync(script);

            script = "var input = document.querySelector('#chat-input');" +

                    "input.dispatchEvent(new KeyboardEvent('keydown', { keyCode: 13, bubbles: true }));";

            browser.ExecuteScriptAsync(script);