[Nexus]

Немного изменил ваш код:

<div class="wrapper">
    <a href="#" class="open-popup" data-popup-id="1">Открыть попап</a>
    <a href="#" class="open-popup" data-popup-id="2">Открыть попап</a>
    <a href="#" class="open-popup" data-popup-id="3">Открыть попап</a>
</div>

<div class="popup__bg" data-popup="1">
    <form class="popup">
        <svg class="close-popup" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path fill="#2982ff" d="M23.954 21.03l-9.184-9.095 9.092-9.174-2.832-2.807-9.09 9.179-9.176-9.088-2.81 2.81 9.186 9.105-9.095 9.184 2.81 2.81 9.112-9.192 9.18 9.1z"/></svg>
        <label>
            <input type="text" name="name">
            <div class="label__text">
                Ваше имя
            </div>
        </label>
        <label>
            <input type="tel" name="tel">
            <div class="label__text">
                Ваш телефон
            </div>
        </label>
        <label>
            <textarea name="message"></textarea>
            <div class="label__text">
                Ваше сообщение
            </div>
        </label>
        <button type="submit">Отправить</button>
    </form>
</div>

<div class="popup__bg" data-popup="2">
    <div class="popup">
        <svg class="close-popup" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path fill="#2982ff" d="M23.954 21.03l-9.184-9.095 9.092-9.174-2.832-2.807-9.09 9.179-9.176-9.088-2.81 2.81 9.186 9.105-9.095 9.184 2.81 2.81 9.112-9.192 9.18 9.1z"/></svg>
        Second
    </div>
</div>

<div class="popup__bg" data-popup="3">
    <div class="popup">
        <svg class="close-popup" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path fill="#2982ff" d="M23.954 21.03l-9.184-9.095 9.092-9.174-2.832-2.807-9.09 9.179-9.176-9.088-2.81 2.81 9.186 9.105-9.095 9.184 2.81 2.81 9.112-9.192 9.18 9.1z"/></svg>
        Third
    </div>
</div>

<style>
* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Montserrat', sans-serif;
}

.wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-evenly;
    width: 100%;
    height: 100vh;
}

.open-popup {
    display: inline-block;
    padding: 15px 30px;
    text-transform: uppercase;
    background: #2982ff;
    color: #fff;
    text-decoration: none;
    font-weight: 500;
    border-radius: 5px;
}

.popup__bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: rgba(0,0,0,0.5);
    opacity: 0;
    pointer-events: none;
    transition: 0.5s all;
}

.popup__bg.active {
    opacity: 1;
    pointer-events: all;
    transition: 0.5s all;
}

.popup {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0);
    background: #fff;
    width: 400px;
    padding: 25px;
    transition: 0.5s all;
}

.popup__bg.active .popup {
    transform: translate(-50%, -50%) scale(1);
    transition: 0.5s all;
}

.close-popup {
    position: absolute;
    top: 10px;
    right: 10px;
    cursor: pointer;
}

.popup label {
    width: 100%;
    margin-bottom: 25px;
    display: flex;
    flex-direction: column-reverse;
}

.popup .label__text {
    font-size: 14px;
    text-transform: uppercase;
    font-weight: 500;
    color: #cfd0d3;
    margin-bottom: 5px;
}

.popup input {
    height: 45px;
    font-size: 18px;
    border: none;
    outline: none;
    border-bottom: 1px solid #cfd0d3;
}

.popup input:focus {
    border-bottom: 1px solid #2982ff;
}

.popup input:focus + .label__text {
    color: #2982ff;
}

.popup textarea {
    resize: none;
    width: 100%;
    height: 150px;
    border: none;
    outline: none;
    border-bottom: 1px solid #cfd0d3;
    font-size: 18px;
    padding-top: 5px;
}

.popup textarea:focus {
    border-bottom: 1px solid #2982ff;
}

.popup textarea:focus + .label__text {
    color: #2982ff;
}

.popup button {
    width: 100%;
    height: 45px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 18px;
    border: 2px solid #2982ff;
    background: #2982ff;
    cursor: pointer;
    text-transform: uppercase;
    transition: 0.5s all;
}

.popup button:hover {
    background: #fff;
    color:#2982ff;
    transition: 0.5s all;
}
</style>
<script>
window.addEventListener('click', e => {
  if (
    !e.target ||
    !e.target.closest('.close-popup') && 
    !e.target.matches('.popup__bg')
  ) {
    return;
  }
  
  e.target.closest('[data-popup]').classList.remove('active');
});

window.addEventListener('click', e => {
  if (!e.target.closest('[data-popup-id]')) {
    return;
  }
  
  const popupId = e.target.closest('[data-popup-id]').dataset.popupId;
  
  document.querySelectorAll(`[data-popup="${popupId}"]`).forEach(node => {
    node.classList.add('active');
  });
});
</script>

Попапы можно делать используя тег dialog.