Odoo CE 16.

On our website on the main shop page i have the categories that the products fall under active and showing on the left- so when i click on a category the products in that category show. which is perfect. 

but then when i click on a product and i go to the product page the category list is gone and in the nav link at the top it just shows  All Products/ "product name" - whatever product we are viewing.

but now to get back to the previous category view i have tor press the back button on the browser. there is no categories on the left and i cant enable it either..

What has everyone else done to bypass this as its frustrating to go back to all products every time then search?