Wordpress Query - SQL query can I return more info to the front end?

Question

I've got a query for my archive page to filter posts based on a custom field. With pre_get_posts I can add the field filter. And with posts_groupby I can clear the SQL GROUP BY since I want to use the posts in order of the meta field. But for me to use it better in the front end I want to either know the meta_id or the meta value.

In the SQL query SELECT SQL_CALC_FOUND_ROWS wp_posts.ID is used. But can I also return the wp_postmeta.meta_value to the front end returned by SELECT? So that I can find the order or info back in $post or $wp_query .

Is this doable?

This is the code I have so far. It returns the posts in the right order, but I want to have it in relation to it's queried meta value. The meta field is a repeater field, so I can't just tell by the post ID.

add_filter( 'pre_get_posts', function ( $query ) {
  if ( is_post_type_archive( [ 'agenda' ] ) && $query->is_main_query() ) {

    $query->set( 'posts_per_page', 4 );
    
    $query->set( 'orderby', 'meta_value' );
    $query->set( 'meta_type', 'DATE' );
    $query->set( 'order', 'ASC' );
    
    $query->set( 'meta_query', array(
      'relation' => 'OR',
      array(
        'relation' => 'OR',
        array(
          'key' => '_start_time_%',
          'compare' => '>=',
          'value' => '2022-01-01 00:00:00',
          'type' => 'DATETIME'
        ),
      ),
    ) );
  }
} );

add_filter( 'posts_groupby', function ( $groupBy, $query ) {
    if (
        is_post_type_archive( [ 'agenda' ] ) &&
        $query->is_main_query() &&
        str_contains( $groupBy, "posts.ID" )
    ) {
        $groupBy = '';
    }
    return $groupBy;
}, 10, 2 );