Sometimes it works, sometimes not. Better than nothing :)

show-password.js

const genericButton = document.querySelector('[type="submit"]')
const password_input = document.querySelector('[type="password"]')
const button = document.createElement('button')

button.setAttribute('type', 'button')
button.innerText = 'Show Password'
button.style = "margin-top: 5px;"

if ( genericButton ) {
  button.setAttribute('class', genericButton.getAttribute('class'))
}

button.onclick = (e) => {
  e.preventDefault()
  const el = document.getElementById(password_input.getAttribute('id'))
  
  if ( el.getAttribute('type') === 'password' ) {
    el.setAttribute('type', 'text')
    button.innerText = 'Hide Password'
  } else {
    el.setAttribute('type', 'password')
    button.innerText = 'Show Password'
  }
}

genericButton.parentNode.appendChild(button)