Hi,
The settings on your screenshots look good.
There is one thing I can think of besides all this:
In each category, you also have a "quantity input method" which will override the "quantity input method" setting of the HikaShop configuration for the products of the category. This can be overridden by the "quantity input" setting of the product itself, but since you set that one to "inherit", it will use the input method from the categories of the product and if they are all set to "inherit", it will use the one from the configuration. So I'm suspecting you might have set that setting to "none" in the category(ies).
And supposing that's the case, you probably did that because you wanted to remove the quantity input from the listings of the products of that category. But what you should have done instead is to change the settings of the menu item / module to turn off the "show quantity input" setting.