[Bug] error de tipo Uncaught TypeError

Uncaught TypeError: Cannot read properties of undefined (reading 'target') me salio ese error al implementar el termino target, si bien estoy siguiendo la logica del programa, no entiendo ese error. el codigo:

const btn = document.querySelector("[data-form-btn]");
console.log(btn);

const createTask = (evento)=>{
    evento.preventDefault();
    const input = document.querySelector("[data-form-input]");
    const value = input.value;

    const list = document.querySelector("[data-list]");
    const task = document.createElement("li");
    task.classList.add("card");
    input.value = "";

    const taskContent = document.createElement("div");

    console.log(checkComplete());


    const titleTask= document.createElement("span");
    titleTask.classList.add("task");
    titleTask.innerText = value;
    taskContent.appendChild(checkComplete());
    taskContent.appendChild(titleTask);

    const content = `
            <i class="fas fa-trash-alt trashIcon icon"></i>`
    // task.innerHTML = content;
    task.appendChild(taskContent);
    list.appendChild(task);
    console.log(content);
};
console.log(btn);
//arrow function o funciones anonimas
btn.addEventListener("click", createTask)

const checkComplete = ()=>{
    const i = document.createElement("i");
    i.classList.add("far","fa-check-square","icon");
    i.addEventListener("click",completeTask());
    return i;
}

const completeTask = (event)=>{
    const element = event.target;
    element.classList.add("fas");
    element.classList.add("completeIcon");
    element.classList.remove("far");
}