how to show products in a category randomly, as well as when using a filter, also show products randomly by default. And displaying Search results in a random order
There is no random order option in Magento by default. Even if you choose "none" the order is not random.
Check out documentation here: https://docs.magento.com/user-guide/catalog/category-products-sort.html
For random order you have to have to look for an extension or create one yourself.