<div class="wrapper">
      <ul class="list__block">
         <li class="item__block">1</li>
         <li class="item__block">2</li>
         <li class="item__block">3</li>
         <li class="item__block">4</li>
         <li class="item__block">5</li>
         <li class="item__block">6</li>
         <li class="item__block">7</li>
      </ul>
   </div>

.wrapper {
   width: 1200px;
   height: 608px;
   background-color: blue;
   margin: auto;
   display: flex;
   align-items: center;
}
.list__block {
   margin-left: auto;
   border: 1px solid red;
   width: 1000px;
   height: 580px;
/*   убери flex */
    display: grid;
  grid-template-columns: repeat(4, 1fr);
  
   overflow-x: scroll;
   overflow-y: hidden;
   gap: 20px;
}
.item__block {
   width: 450px;
   height: 247px;
   background: red;
}