Elementor – Sort by name

I don’t know much about elementor, but to keep this as a Purely WordPress answer you need to change your query to sort by post name. The code you provided looks like a pre-query filter so you should try this:

add_action( 'elementor/query/kunst_op_kunstenaar', function( $query ) {
    
  $query->set( 'order', 'ASC');
  $query->set( 'orderby', 'title');
}

This sets your order by function to sort by title and then order to ascending (a-z).