Demo Import Failed - Now Stuck on Restoring Theme Options

I tried installing a pre-built site, but this didn't complete after me waiting over 25 minutes.

I had to refresh the page, which has then created a few issues as the theme half-installed. I consistently get a message:

Existing Site Import Detected
It is highly recommended that you remove the last site you imported before importing a new one.

This process restores your previous options, widgets and active plugins. It will also remove your imported content and CSS.

Remove Imported Site Skip

I'm trying to restore the theme but it's now stuck on restoring, but again nothing is working.

ON WPdebug I get the error SELECT COUNT( id ) AS total FROM wp_nf3_forms;

This error didn't exist before I installed GeneratePress/Elementor.
I've had to reinstall my old theme for the time being as I can't have my website offline.

Please help! :)