Unable to append element on a list item

I am unable to add a delete button to a list item in my code, pls I need assistance. Below is my code

function addDeleteBtn() {
  const ul = document.querySelector("ul");
  let li = document.querySelectorAll("li");
  let btn = document.createElement("button");
  const text = document.createTextNode("delete");
  btn.appendChild(text);
  for (const item of li) {
    li.append(btn);
  }

  ul.appendChild(li);
}
addDeleteBtn();