Well,
I fixed my own problem. If someone needs it in the future, you can use the code below:
$query = new WP_Query( array(
'cat' => '22',
'posts_per_page' => -1,
'orderby' => 'meta_value',
'meta_key' => 'meta_key_here',
'order' => 'DESC',
'fields' => 'ids'
));
global $post;
$i = array_search( $post->ID, $query->posts ) + 1;
echo '<div class="ranks">';
echo '<a href="https://wordpress.stackexchange.com/...">Post Ranking: </a>';
echo "{$i}";
echo '</div>';
for tag:
$query = new WP_Query( array(
'tag_id' => '22',
'posts_per_page' => -1,
'orderby' => 'meta_value',
'meta_key' => 'meta_key_here',
'order' => 'DESC',
'fields' => 'ids'
));
global $post;
$i = array_search( $post->ID, $query->posts ) + 1;
echo '<div class="ranks">';
echo '<a href="https://wordpress.stackexchange.com/...">Post Ranking: </a>';
echo "{$i}";
echo '</div>';