Hello,
1) If you have a lower PHP Memory limit than required you may face issues with the functionality of the bundled plugins and theme while using it. So, we would recommend you to contact your hosting and increase the limit.
2) I have checked your site and see that you installed the Elementor version of the Books demo and all the content is in place. Only 2 sliders are missing because you need to edit these sliders and choose the product categories you would like to show there https://prnt.sc/whauzd
So, could you, please, explain what else is different on your installation comparing to the demo?
3) If you changed your mind and want to install the WPBakery version use the WP Database Reset plugin https://wordpress.org/plugins/wordpress-database-reset/ to reset your installation and go through the setup wizard again and choose the WPBakery demo.
Regards