SUMMARY
The number of often used applications that are shown in the Application Menu/Dashboard depends on how many favorites score as most used applications in the "resource score cache". In the following, I assume that 14 is the hard coded maximum number of often used applications shown in the menu.

STEPS TO REPRODUCE
1. Start with no favorites and more than 14 applications with a score in the resource score cache.
2. Set (for example) 12 of the often used applications shown in the menu as favorites.

OBSERVED RESULT
Only 2 applications are shown as often used and no more than that, no matter how high the cached score of any other application is.

EXPECTED RESULT
The menu should show the configured number of often used applications, or less only if there are not enough applications recorded in the cache. It makes sense to exclude often used favorites from the often used application selection, but this shouldn't decrease the total number of often used applications shown in the menu.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: openSUSE Tumbleweed 20210524
KDE Plasma Version: 5.21.5
KDE Frameworks Version: 5.82.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
I use the following command to check the score of often used applications:
$ sqlite3 -header -column $HOME/.local/share/kactivitymanagerd/resources/database "SELECT targettedResource,cachedScore FROM ResourceScoreCache WHERE initiatingAgent IS 'org.kde.plasma.kicker' ORDER BY cachedScore DESC;"