Zend certified PHP/Magento developer

Admin Dashboard not working after adding Sirena theme (from envato marketplace)

I purchased Magento Theme from Envato Marketplace & added to my store as per there guidelines. Tried many different times and on different servers & at last when logging into the admin panel, I’m getting error Exception #0 (OutOfRangeException): Specified invalid parent id (Meigee_Core::themes)

Full Error

1 exception(s):
Exception #0 (OutOfRangeException): Specified invalid parent id (Meigee_Core::themes)

Exception #0 (OutOfRangeException): Specified invalid parent id (Meigee_Core::themes)
#1 MagentoBackendModelMenuBuilderInterceptor->___callParent('getResult', array(&MagentoBackendModelMenu#000000003d662cea0000000050a71442#)) called at [vendor/magento/framework/Interception/Interceptor.php:138]
#2 MagentoBackendModelMenuBuilderInterceptor->MagentoFrameworkInterception{closure}(&MagentoBackendModelMenu#000000003d662cea0000000050a71442#) called at [vendor/magento/framework/Interception/Interceptor.php:153]
#3 MagentoBackendModelMenuBuilderInterceptor->___callPlugins('getResult', array(&MagentoBackendModelMenu#000000003d662cea0000000050a71442#), array(array('SetupMenuBuilder'))) called at [generated/code/Magento/Backend/Model/Menu/Builder/Interceptor.php:39]
#4 MagentoBackendModelMenuBuilderInterceptor->getResult(&MagentoBackendModelMenu#000000003d662cea0000000050a71442#) called at [vendor/magento/module-backend/Model/Menu/Config.php:148]
#5 MagentoBackendModelMenuConfig->_initMenu() called at [vendor/magento/module-backend/Model/Menu/Config.php:111]
#6 MagentoBackendModelMenuConfig->getMenu() called at [vendor/magento/module-backend/Model/Url.php:364]
#7 MagentoBackendModelUrl->_getMenu() called at [vendor/magento/module-backend/Model/Url.php:324]
#8 MagentoBackendModelUrl->getStartupPageUrl() called at [vendor/magento/module-backend/App/AbstractAction.php:281]
#9 MagentoBackendAppAbstractAction->_processUrlKeys() called at [generated/code/Magento/Backend/Controller/Adminhtml/Index/Index/Interceptor.php:50]
#10 MagentoBackendControllerAdminhtmlIndexIndexInterceptor->_processUrlKeys() called at [vendor/magento/module-backend/App/Request/BackendValidator.php:175]
#11 MagentoBackendAppRequestBackendValidator->validate(&MagentoFrameworkAppRequestHttp#000000003d662fc20000000050a71442#, &MagentoBackendControllerAdminhtmlIndexIndexInterceptor#000000003d662cf20000000050a71442#) called at [vendor/magento/framework/App/Request/CompositeValidator.php:40]
#12 MagentoFrameworkAppRequestCompositeValidator->validate(&MagentoFrameworkAppRequestHttp#000000003d662fc20000000050a71442#, &MagentoBackendControllerAdminhtmlIndexIndexInterceptor#000000003d662cf20000000050a71442#) called at [vendor/magento/framework/App/FrontController.php:138]
#13 MagentoFrameworkAppFrontController->processRequest(&MagentoFrameworkAppRequestHttp#000000003d662fc20000000050a71442#, &MagentoBackendControllerAdminhtmlIndexIndexInterceptor#000000003d662cf20000000050a71442#) called at [vendor/magento/framework/App/FrontController.php:99]
#14 MagentoFrameworkAppFrontController->dispatch(&MagentoFrameworkAppRequestHttp#000000003d662fc20000000050a71442#) called at [vendor/magento/framework/Interception/Interceptor.php:58]
#15 MagentoFrameworkAppFrontControllerInterceptor->___callParent('dispatch', array(&MagentoFrameworkAppRequestHttp#000000003d662fc20000000050a71442#)) called at [vendor/magento/framework/Interception/Interceptor.php:138]
#16 MagentoFrameworkAppFrontControllerInterceptor->MagentoFrameworkInterception{closure}(&MagentoFrameworkAppRequestHttp#000000003d662fc20000000050a71442#) called at [vendor/magento/framework/Interception/Interceptor.php:153]
#17 MagentoFrameworkAppFrontControllerInterceptor->___callPlugins('dispatch', array(&MagentoFrameworkAppRequestHttp#000000003d662fc20000000050a71442#), array(array('default_store_se...', 'page_cache_from_...', 'storeCookieValid...', 'install', 'configHash'))) called at [generated/code/Magento/Framework/App/FrontController/Interceptor.php:26]
#18 MagentoFrameworkAppFrontControllerInterceptor->dispatch(&MagentoFrameworkAppRequestHttp#000000003d662fc20000000050a71442#) called at [vendor/magento/framework/App/Http.php:137]
#19 MagentoFrameworkAppHttp->launch() called at [generated/code/Magento/Framework/App/Http/Interceptor.php:24]
#20 MagentoFrameworkAppHttpInterceptor->launch() called at [vendor/magento/framework/App/Bootstrap.php:261]
#21 MagentoFrameworkAppBootstrap->run(&MagentoFrameworkAppHttpInterceptor#000000003d662fb00000000050a71442#) called at [index.php:39]

I’m using Magento 2.3.2 on AWS Lightsail.

I have wasted 2 days on Google to avoid this issue but no success.

I might be missing some basic stuff, I don’t know, but any help will be highly appreciated.