Hello,

It seems that you haven’t set the page builder to Wp-Bakery from Theme Settings >> General before importing the demo.

Screenshot for Clarification: https://prnt.sc/10e7uky

Please make a fresh install by reinstalling wordpress then install the theme and the recommended plugins.

Then you can re import the demo. And make sure that the page builder is set to Wp-Bakery from theme settings as mentioned in the screenshot.

OR

You can reset your website using Wp Reset plugin and then try installing the theme again and import the demo.

https://wordpress.org/plugins/wp-reset/

Best Regards.