Modifying Formspree code to send contact responses to email – HTML/CSS/JS

I have the following form:

/* Contact Form */

input[type=text],
[type=email],
select,
textarea {
  width: 100%;
  padding: 12px;
  border: 1px solid #555;
  margin-top: 6px;
  margin-bottom: 16px;
  resize: vertical;
}

input[type=submit] {
  background-color: #0563bb;
  color: white;
  padding: 12px 20px;
  border: none;
  cursor: pointer;
}

input[type=submit]:hover {
  opacity: 0.9;
}

.contactform {
  position: relative;
  border-radius: 50px;
  background-color: #f2f2f2;
  padding: 5px;
  z-index: 2;
  display: block;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: auto;
  margin-top: 1%;
  width: 100%;
  animation-name: gradient;
  animation-duration: 3s;
  animation-iteration-count: infinite;
}

.contactform:hover {
  animation-name: gradient;
  animation-duration: 15s;
  animation-iteration-count: infinite;
}

.column {
  float: center;
  width: 50%;
  margin-top: 6px;
  padding: 20px;
  display: block;
  margin-left: auto;
  margin-right: auto;
}

.row:after {
  content: "";
  display: table;
  clear: both;
}

@media screen and (max-width: 600px) {
  .column,
  input[type=submit] {
    width: auto;
    margin-top: 0;
  }
}

@keyframes shake {
  10%,
  90% {
    transform: translate3d(-1px, 0, 0);
  }
  20%,
  80% {
    transform: translate3d(2px, 0, 0);
  }
  30%,
  50%,
  70% {
    transform: translate3d(-4px, 0, 0);
  }
  40%,
  60% {
    transform: translate3d(4px, 0, 0);
  }
}

<section id="contact">
  <div class="container" data-aos="fade-up">
    <div class="contactform">
      <div style="text-align:center">
        <div class="section-title">
          <h2><br/>Get In Touch</h2>
        </div>
        <p>Feel Free To Reach Out To Me Through This Form! </p>
      </div>
      <div class="row">
        <div class="column">
          <form name="myform" action="https://formspree.io/f/xdobkgny" method="POST" novalidate>
            <label for="firstname">First Name</label>
            <input type="text" id="first name" name="firstname" placeholder="Your First Name.." required>
            <label for="lastname">Last Name</label>
            <input type="text" id="lastname" name="lastname" placeholder="Your Last Name.." required>
            <label for="email">Email:</label>
            <input type="email" id="email" name="email" placeholder="Your Email.." required>
            <label for="subject">Subject</label>
            <textarea id="subject" name="subject" placeholder="Lets Collaborate.." style="height:170px" required></textarea>
            <input type="submit" value="Submit">
          </form>
        </div>
      </div>
    </div>
  </div>
</section>

This form is sending responses to the desired email, however I want to change the redirection page to thankyou.html instead of the Formspree redirection page. How would I modify this following JS code? This JS code also has some other information such as error messages…etc but I already got that covered so can I just remove that part? Essentially, the only thing I want to change is redirection on the submission and dont want any errors or any other info. The only reason I am using the JS code provided by Formspree is to change the redirection and nothing else. How would this be possible? I want to remove text such as Thanks for your submission! and Oops...... which is provided in the following JS code since I already have that covered with my own js code in my file.

JS code:

var form = document.getElementById("my-form");
    
    async function handleSubmit(event) {
      event.preventDefault();
      var status = document.getElementById("my-form-status");
      var data = new FormData(event.target);
      fetch(event.target.action, {
        method: form.method,
        body: data,
        headers: {
            'Accept': 'application/json'
        }
      }).then(response => {
        status.innerHTML = "Thanks for your submission!";
        form.reset()
      }).catch(error => {
        status.innerHTML = "Oops! There was a problem submitting your form"
      });
    }
    form.addEventListener("submit", handleSubmit)