however the sidebar is showing an add new listing button at the top of the sidebar
The button is in the header menu which is dependent upon the page template (and within a separate file). It has no impact with or without a sidebar.
It seems that the widgets are not being recognized.
Under Appearance > Widgets make sure that the widgets are placed in the proper sidebar column. There is one for Blog Sidebar (for blog pages) and one for Page Sidebar (for standard pages with sidebars).
Looks like using the [PAGE – BLOG] page template and placing the WP widgets in the Blog Sidebar column would be about the extent of it without getting into Elementor or manual changes.