Looking for a product filtering solution

Hi there.
First of all, thank you for an amazing theme!

I’m trying to set up a widget (product categories) in my Shop page’s left sidebar, but it seems like I have 2 widget areas that are not showing up. I can edit all the widgets in the “Appearance > widgets”, but not in the live preview and the widget don't show up.

I’ve tried to disable all plugins but it seems like the problem persists. My settings:
- on shop page, lay-out: set on sidebar left
- in functions.php, added code: add_filter( 'generate_sections_sidebars','__return_true' );
- on widgets page: added the desired widget under the left sidebar and clicked on "done"
- in customizer: layout-sidebars. Set the sidebar layout to "sidebar-content (the sidebar blog + sidebar single post is set to "content (no sidebar)"

The “missing” widget areas seem to be “Right sidebar, “Left sidebar”.

When I’m using the live preview editor I get an error message saying “Your theme has 2 other widget areas, but this particular page doesn’t display them. You can navigate to other pages on your site while using the Customiser to view and edit the widgets displayed on those pages.”

Thanks in advance,

I’m using a childtheme and:
GP premium Version 1.12.3
GeneratePressVersion: 3.0.2
Build the site with Generateblocks

I also tried this solution: https://generatepress.com/forums/topic/product-filter-in-off-canvas-menu/
but since I'm not an expert I got stuck. I don't see the off canvas menu on my shop.