E_ERROR Line 1

Hello support team,

Can you please help me to fix the following? Recovery mode doesn’t work and I cannot access the backend.

Thank you in advance
____

Versione di WordPress 5.8.6
Tema corrente: Highend (versione 3.4.1)
Versione PHP 8.1.17

Dettagli dell’errore
====================
Un errore di E_ERROR è stato causato nella linea 1 del file /home/fuscosim/www/ristobarlulivo.ch/wp-content/themes/HighendWP/functions/image_dimensions.php. Messaggio di errore: Uncaught Error: Array callback must have exactly two elements in /home/fuscosim/www/ristobarlulivo.ch/wp-content/themes/HighendWP/functions/image_dimensions.php:1
Stack trace:
#0 /home/fuscosim/www/ristobarlulivo.ch/wp-content/themes/HighendWP/functions.php(281): include()
#1 /home/fuscosim/www/ristobarlulivo.ch/wp-settings.php(546): include(‘/home/fuscosim/…’)
#2 /home/fuscosim/www/ristobarlulivo.ch/wp-config.php(93): require_once(‘/home/fuscosim/…’)
#3 /home/fuscosim/www/ristobarlulivo.ch/wp-load.php(50): require_once(‘/home/fuscosim/…’)
#4 /home/fuscosim/www/ristobarlulivo.ch/wp-login.php(12): require(‘/home/fuscosim/…’)
#5 {main}
thrown