Fatal Error with PHP 8

Hello,
I have upgrade my PHP to 8 due to no longer support for PHP 7.4 but your plugin is not being activated now and generating this error

Fatal error: Uncaught Error: Attempt to assign property “plugins” on bool in /customers/9/a/6/hiddendomain.com/httpd.www/wp-content/plugins/add-search-to-menu.backup/includes/freemius/start.php:74 Stack trace: #0 /customers/9/a/6/hiddendomain.com/httpd.www/wp-content/plugins/add-search-to-menu.backup/includes/freemius.php(19): require_once() #1 /customers/9/a/6/hiddendomain.com/httpd.www/wp-content/plugins/add-search-to-menu.backup/includes/freemius.php(44): is_fs() #2 /customers/9/a/6/hiddendomain.com/httpd.www/wp-content/plugins/add-search-to-menu.backup/add-search-to-menu.php(195): require_once(‘/customers/9/a/…’) #3 /customers/9/a/6/hiddendomain.com/httpd.www/wp-admin/includes/plugin.php(2314): include_once(‘/customers/9/a/…’) #4 /customers/9/a/6/hiddendomain.com/httpd.www/wp-admin/plugins.php(192): plugin_sandbox_scrape(‘add-search-to-m…’) #5 {main} thrown in /customers/9/a/6/hiddendomain.com/httpd.www/wp-content/plugins/add-search-to-menu.backup/includes/freemius/start.php on line 74

Please help fix it, i am stuck now and my visitors cannot use search.