Pagination for search page - php

Question

I want to make a pagination for search results. I can see the results in first page when I use the search box but I can't see the other results in other pages. What am I doing wrong?
I would be really glad if you could help me
Here' my search page codes.
Codes for pagination
<?php
if(isset($_GET["page"])) {
$page = $_GET["page"];
}else {
$page = "";
}
if($page == "" || $page == 1) {
$starter_post = 0;
} else {
$starter_post = ($page * 6) - 6;
}
$sql_query2 = "SELECT * FROM posts ";
$look_all_post = mysqli_query($conn, $sql_query2);
$all_post_count = mysqli_num_rows($look_all_post);
$page_number = ceil ($all_post_count / 6);
Codes for search results
if(isset($_POST["searchbtn"])) {
$search = $_POST["search"];
$query = "SELECT * FROM posts WHERE post_tags LIKE '%$search%' ORDER BY post_id DESC LIMIT $starter_post, 6";
$search_query = mysqli_query($conn, $query);
if(!$search_query) {
die("QUERY FAILED:". mysqli_error($conn));
}
$search_count = mysqli_num_rows($search_query);
if($search_count == 0) {
echo "<h3> No Result </h3>";
} else {
while ($row = mysqli_fetch_assoc($search_query)){
$post_id = $row["post_id"];
$post_date = $row["post_date"];
$date = strtotime($post_date);
$newdate = date("d/m/Y", $date);
$post_title = $row["post_title"];
$post_text = $row["post_text"];
$post_image = $row["post_image"];
?>
<div class="col-md-6">
<div class="blog">
<div class="blog-img ">
<img src="images/<?php echo $post_image; ?>" class="img-fluid" >
</div>
<div class="blog-content">
<ul class="blog-meta">
<li><i class="far fa-calendar-alt"></i><span class="writer"><?php
echo $newdate; ?></span></li>
</ul>
<h3><?php echo $post_title; ?></h3>
<p><?php echo $post_text; ?></p>
<div class="blog-content2 text-center">
</div>
</div>
</div>
</div>
<?php }
}
}
?>
Codes for pagination
</div>
<div class="row">
<nav aria-label="Page navigation example">
<ul class="pagination justify-content-center">
<li <?php if ($page == 1 or $page == "") {echo "class='page-item disabled'";} ?>>
<a class="page-link" href="search.php?page=<?php if ($page > 1) {echo $page - 1;} ?>">Previous</a>
</li>
<?php //Pagination Continue
for($i=1; $i<=$page_number; $i++) {
echo "<li class='page-item'><a class='page-link' href='search.php?page=$i'>{$i}</a></li>";
}
?>
<li <?php if ($page == $page_number) {echo "class='page-item disabled'";} ?>>
<a class="page-link" href="search.php?page=<?php if ($page == "") {echo $page = 2;} else if($page_number!=$page){echo $page+1;} else if($page_number==$page){echo $page;}?>">Next</a>
</li>
</ul>
</nav>
</div>