Hi there!
Thanks for your query!
Please use the unique ID of the page and then apply the following custom css to get the page lrt.
#sp-page-builder{
direction: ltr;
}
You need to add the unique ID of the page!
Page builder works within the component area, so when you set fluid row option it's full width or covering the total 12 column gridwith respect to the component area set by the template.
The template you are using is not from us! And I guess you are using boxed layout or something like that!
Note: Customization support is prohibited here!
Best Regards