Unmet dependencies for MySQL Workbench

Check if you are using third party repositories. If so disable them, since they are a common source of problems.
Furthermore run the following command in a Terminal: apt-get install -f
Transaction failed: The package system is broken
 The following packages have unmet dependencies:

mysql-workbench-community: Depends: libmysqlclient21 (>= 8.0.11) but it is not installed
                           Depends: libstdc++6 (>= 9) but 10.2.0-5ubuntu1~20.04 is installed
                           Depends: zlib1g (>= 1:1.2.0) but 1:1.2.11.dfsg-2ubuntu1.1 is installed