Filtering and ordering by ACF

Hello, I have created something like Event manager with CPT + ACF. So I am using the “event_date” custom field (type datepicker), which could be simply different from publish_date (coming from WP core…).

I need to do two things now
1. Filter CPT, which are next, and which are past (based on $today variable – if greather than -> next, else past) – THIS IS DONE
2. Order posts by ACF – “event_date”, now my posts are ordered by publish date, which is not correct.

This is my code:

function lava_show_next_events($query) {
    //var_dump($query);
    $today = date('Ymd');
    
    $meta_query = $query->get( 'meta_query' );

    if ( ! $meta_query ) {
        $meta_query = [];
    }

    $meta_query[] = 
        array(
            'key' => 'datum_zaciatku',
            'value' => $today,
            'compare' => '>',
            'order_by' => 'datum_zaciatku',
            'order' => 'ASC'
        );

    //var_dump($meta_query);    

    $query->set( 'meta_query', $meta_query );
    //var_dump($query);
}

add_action( 'elementor/query/lava-next-events', 'lava_show_next_events',10 );

I am using Elementor with query ID, so I am trying to catch the query of CPT and update ordering. I was able to filter only future events, however ordering by ACF doesn’t work.

Note: datum_zaciatku means event_date ??