Ok, I looked through the code and you can prevent them from showing up when viewing a product by setting the manufacturer to "un-published". I do not know what other effects that might have for how you intend to use them, though the docs make it sound like it should only affect the frontend:https://docs.nopcommerce.com/en/running-your-store/catalog/manufacturers.htmlSelect the Published checkbox, to enable the manufacturer to be visible in the public store.
It's also easy to edit the cshtml files. For example, in Nop.Web / Views / Product / ProductTemplate.Simple.cshtml you would simply comment out this line:
@await Html.PartialAsync("_ProductManufacturers", Model.ProductManufacturers)
It's also feasible to implement your own setting, but would require editing the source code.