Comment 9 for bug 1905061

Thanks Erich, that's what I didn't know, evereyday something to learn. I had to downgrade the package first with

sudo apt-get install ubuntustudio-menu=0.49

This indeed asked me to overwrite the modified file and I got the overpopulated menu back.
Upgrading the package with

sudo apt-get install ubuntustudio-menu=0.50~20.10.1

solved the issue with the overpopulated menu. Just perfect.

By the way, I didn't like the subfolders in the "Games"-folder since there are not many games installed and I'm not planning to do so. I wrote a games.menu file which can be placed in
/etx/xdg/menus/applications-merged or in ~/.config/menus/applications-merged . Here it is:

<!DOCTYPE Menu PUBLIC "-//freedesktop//DTD Menu 1.0//EN" "http://www.freedesktop.org/standards/menu-spec/menu-1.0.dtd">
<Menu>
    <Name>Applications</Name>
    <Menu>
  <Name>Games</Name>
  <Directory>kf5-games.directory</Directory>
  <Menu>
   <Name>Arcade</Name>
   <Directory>ubuntustudio-noshow.directory</Directory>
  </Menu>
  <Menu>
   <Name>Board</Name>
   <Directory>ubuntustudio-noshow.directory</Directory>
  </Menu>
  <Menu>
   <Name>Card</Name>
   <Directory>ubuntustudio-noshow.directory</Directory>
  </Menu>
  <Menu>
   <Name>Kidsgames</Name>
   <Directory>ubuntustudio-noshow.directory</Directory>
  </Menu>
  <Menu>
   <Name>TacticStrategy</Name>
   <Directory>ubuntustudio-noshow.directory</Directory>
  </Menu>
  <Menu>
   <Name>Logic</Name>
   <Directory>ubuntustudio-noshow.directory</Directory>
  </Menu>
        <Include>
            <Category>Game</Category>
        </Include>
    </Menu>
</Menu>

Feel free to use it or not.