rclpris
If you want to hide sidebar on specific page, it will be simple.
Go to menu item of this page >> Page Display >> add a page class for it:

For example, I add 'hideSidebar' class.
Then you can use this custom CSS:
.com_content.view-category.hideSidebar .t4-main-body .t4-row>div.sidebar-r {
display: none;
}
It will hide the sidebar on this page.