Cant Export site with 8000 pages

Hi, I want to export all the sub pages of the site (there are 5 main pages) and one of these has 8000+ sub pages. I want to still have wp as the main site and all the sub pages I want to be served in html.

How can I approach this?
All that happens when I try the plugin is that it creates the wp-content folder but no pages and it gives no errors (says done)

I have used the plugin before and loved it but dont understand what I am doing wrong.

Thanks.

https://www.ads-software.com/plugins/really-static/