You are talking about adding a View block to a page to show some posts?
There isn't a front-end control to specify how many posts to show. You can add pagination controls, so that, say, 10 results show at a time and then the users page through the results, but I'm not sure that meets your needs.
Are you using the block builder for view ? If so then I would recommend doing this in the classic editor because it provides more flexibility when it comes to implementing custom solutions.
If your view is already built with the block editor then it will need to be remade.
If the classic view hasn't been enabled you can enable it by going to Toolset -> Settings and scrolling to Editing Experience. From there I recommend that you select " Show both the legacy and Blocks interface and let me choose which to use for each item I build".
This will allow you to have access to the classic editor as well as the block editor. From there refresh the page and go to Toolset -> Views.
Please let me know if this helps or if further clarification is needed.