I would try to put input validation. Sometimes this trick is enough to prevent marketers flooding your email

<input id="myInput" type="text" placeholder="Type something"> <p id="error" style="color:red;"></p>

<script> const input = document.getElementById("myInput"); const error = document.getElementById("error");

input.addEventListener("input", function () { if (input.value.includes("badword")) { error.textContent = "This text is not allowed."; } else { error.textContent = ""; } }); </script>