I’m not exactly sure what you mean with app page. Are you talking about the home page/Dashboard on Brave Desktop and the top pages (bookmarks).
With version 0.69, which is Brave dev at the moment you can disable them comletly (see the new Dashboard settings on my screenshot). It’s not available yet in the release version or beta version!
The Brave team is currently working on improving the Dashboard, so options to add you own bookmarks and have more than 6 will presumably come very soon.
Just wanted to mention that we also have a category for feature requests. One for desktop, iOS and android, which helps keeping the forum organised and people know about which Brave version you talk.