<script src="https://api-maps.yandex.ru/2.1/?lang=ru_RU&amp;apikey=<ваш API-ключ>" type="text/javascript"></script>

<div class="map" id="map"></div>
<div class="map" id="mapHidden"></div>

.map{
  height: 500px;
  width: 50%;
  display: inline-block;
  float: left;
}

ymaps.ready(init);

function init() {
  let maps = [];
  
  maps.push(new ymaps.Map("map", {
    center: [57.114015436771, 65.559661239335],
    zoom: 16,
    controls: []
  }), new ymaps.Map("mapHidden", {
    center: [57.114015436771, 65.559661239335],
    zoom: 16,
    controls: []
  }));
  for (const map of maps) {
    map.geoObjects.add(new ymaps.Placemark([57.113723585592, 65.560315698335], {
      hintContent: '',
      balloonContent: ''
    }));
  }
}