Wordpress sort order by ACF text field - wordpress

Question

I have an issue that is doing my head in, I'm trying to sort my posts using pre_get_posts by and ACF field that is a text field.
Here is my code:
function my_pre_get_posts( $query ) {
// do not modify queries in the admin
if( is_admin() ) {
return $query;
}
if( $query->is_main_query() && $query->is_tax('locations')) {
$query->set('meta_key', 'level');
$query->set('orderby', 'meta_value');
$query->set('order', 'DESC');
}
// return
return $query;
}
add_action('pre_get_posts', 'my_pre_get_posts');
In the ACF config, it's set to text and the values of this text can be Bronze, Silver, Gold etc.
UPDATE
I've now changed the level field to a number and switch it round 1 = Bronze, 2 = Silver etc.
Still, I get nothing.
When I run the below nothing gets returned.
Any ideas?

Answer 1

I think you could be inadvertently overwriting the whole query. Try this (untested) snippet:
function my_pre_get_posts( $query ) {
if( ! is_admin() && $query->is_main_query() && $query->is_tax('locations')) {
$query->set('meta_key', 'level');
$query->set('orderby', 'meta_value');
$query->set('order', 'DESC');
}
}
add_action('pre_get_posts', 'my_pre_get_posts');
Note that $query is not returned.
Good luck!

Answer 2

So in the end of switched it from the functions.php file to the taxonomy template.
Here is my finished code:
<?php
if(isset($_GET['type'])) {
if($_GET['type'] == 'villa') {
$filter = array(
'key' => 'type_name',
'value' => 'Villa',
'compare' => '=',
);
} elseif ($_GET['type'] == 'apartment') {
$filter = array(
'key' => 'type_name',
'value' => 'Apartment',
'compare' => '=',
);
} elseif ($_GET['type'] == 'alls') {
$filter = array(
'relation' => 'or',
array(
'key' => 'type_name',
'value' => 'Villa',
'compare' => '=',
),
array(
'key' => 'type_name',
'value' => 'Apartment',
'compare' => '=',
)
);
}
}
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
$args = array(
'post_type' => 'properties',
'post_per_page' => 12,
'paged' => $paged,
'meta_key' => 'level',
'orderby' => 'meta_value',
'order' => 'DESC',
'tax_query' => array(
array(
'taxonomy' => 'locations',
'field' => 'slug',
'terms' => $term->slug,
),
),
'meta_query' => $filter
);
// the query
$the_query = new WP_Query( $args ); ?>
Fingers crossed it helps someone else.