I have a similar error when I try to access configuration in CB control panel: Timeout after 30 seconds.
the last lines of system debug are:
40 30.1023 23638784 CBLib\AhaWow\View\RegistryEditView->_form_custom( $name = '', $value = NULL, $node = class CBLib\Xml\SimpleXMLElement { public $@attributes = }, $control_name = 'params' ) .../RegistryEditView.php:3507
41 30.1023 23639656 call_user_func_array:{/var/www/clients/client7/web11/web/libraries/CBLib/CBLib/AhaWow/View/RegistryEditView.php:4725}( $callback = [0 => class CBLib\Image\Test { }, 1 => 'Gmagick'], $args = [0 => '', 1 => NULL, 2 => 'params'] ) .../RegistryEditView.php:4725
42 30.1023 23639728 CBLib\Image\Test->Gmagick( '', NULL, 'params' )
This only occurs, when I use PHP 8 (8.0.3 ). When I switch back to 7.4 there is no timeout.
Maybe this information is helpful.
Kind Regards
Markus