Taxonomy Image on Custom Post Type

Hi,

regarding to this topic https://support.metabox.io/topic/taxonomy-image-on-custom-post-type/ I try to display in Image field of a custom term on the post display.

I try to make a shordcode like this:

function custom_shortcode() {

	$terms = get_the_terms( get_queried_object_id(), 'language' );
	foreach ( $terms as $term ) {
	    $term_image = rwmb_meta( 'term_flag', ['object_type' => 'term'], $term->term_id );
	    if( is_array( $term_image ) ) {
	        echo '<img src="'. $term_image['full_url'] .'">'; 
	        echo '<pre>'; // just for debugging
	        var_dump($term_image); // just for debugging
	        echo '</pre>'; // just for debugging
	    }
	}

}
add_shortcode( 'termimage', 'custom_shortcode' );

I get an php warning:
Undefined array key "full_url"

This is the output of the var_dump:

array(1) {
  [385]=>
  array(15) {
    ["width"]=>
    int(40)
    ["height"]=>
    int(24)
    ["file"]=>
    string(15) "2022/03/de1.png"
    ["sizes"]=>
    array(0) {
    }
    ["image_meta"]=>
    array(12) {
      ["aperture"]=>
      string(1) "0"
      ["credit"]=>
      string(0) ""
      ["camera"]=>
      string(0) ""
      ["caption"]=>
      string(0) ""
      ["created_timestamp"]=>
      string(1) "0"
      ["copyright"]=>
      string(0) ""
      ["focal_length"]=>
      string(1) "0"
      ["iso"]=>
      string(1) "0"
      ["shutter_speed"]=>
      string(1) "0"
      ["title"]=>
      string(0) ""
      ["orientation"]=>
      string(1) "0"
      ["keywords"]=>
      array(0) {
      }
    }
    ["ID"]=>
    string(3) "385"
    ["name"]=>
    string(7) "de1.png"
    ["path"]=>
    string(111) "/var/www/vhosts/t36updxb.web5.alfahosting-server.de/mylistingshowcase.online/wp-content/uploads/2022/03/de1.png"
    ["url"]=>
    string(67) "https://mylistingshowcase.online/wp-content/uploads/2022/03/de1.png"
    ["full_url"]=>
    string(67) "https://mylistingshowcase.online/wp-content/uploads/2022/03/de1.png"
    ["title"]=>
    string(5) "de[1]"
    ["caption"]=>
    string(0) ""
    ["description"]=>
    string(0) ""
    ["alt"]=>
    string(0) ""
    ["srcset"]=>
    bool(false)
  }
}

Can you please assist and tell me where is my mistake?
I'm a non professionell developer.

Thank you!