Sorry, I don't understand the issue.
A category list shows a list of categories, or a category tree i.e. also the child categories.
A category blog shows a list of articles in a category. This is intended behaviour.

Hi, the "Category List" is described as "Displays a list of articles in a category" and infact in J3 it displays the list of articles in the selected category. In J4 it shows no article, but clicking on "clear" on the filter, the articles do appear, but navigation does not work.

@chmst Well, the help page indeed tells that it shows articles: https://docs.joomla.org/Help4.x:Menu_Item:_Category_List

@Giuse69 Maybe something wrong with permissions for the categories or the particular articles? Or with the "List Layouts" setting of the menu item? Could you check on the J4 help page which I've linked if everything is right?

@chmst Maybe you had this one in mind? https://docs.joomla.org/Help4.x:Menu_Item:_List_All_Categories

@richard67: I checked and I see no strange settings. I created a new menu item from scratch pointing to that category and again no article is shown. As described in the first post, if I click on the "clear" button of the title search, results do appear...

Hi, any update on this? If you can re-read the initial post, the behavior is very suspicious of a bug/conflict: no article is returned with the Category List on the first page load, then clicking on the "Clear" button of the title filter makes the page reload with articles listed. Also every interaction with the filter (like typing a char and press enter) makes the articles appear.
So it's not an issue of permission or menu configuration since using the filter, the articles in that category do show.
thanks for you feedback

I finally found that the problem is due to a bug in Seblod opened 2 days ago: Octopoos/SEBLOD#750
So I am closing this for Joomla
thanks

Thanks to @bembelimen for finding the source of the bug, you already helped at least 2 persons. :-)