List your main product categories in your menu’s level 1.
Show them directly in the menu (on both desktop and mobile).
In my experience, you can usually fit up to 10 categories in the menu, but less is more. Around 3-7 category menu items is best.
The exception to this is if you have several other very important pages besides your product categories which you also want to list in the level 1 of the menu. In that case, you can have a “Shop” or “Departments” or “Products” menu item then the other non-category menu items.
On mobile, make sure those categories and the post-sale menu items (Order Tracking, customer support…) fit on one screen. So you may want to have an expandable “More” item to reduce your total number of menu items.