English also has cases, we just don’t think of them much. It’s why pronouns are typically given as nominative/objective pairs: she/her, they/them, etc. So, similarly in German you’d probably only need to give one or two examples to make it clear which set to use. Or give all four.
Enjoy your stable systems while you can! Learning comes through solving problems as they come up. It’s a good sign if you don’t have to.
Need some new functionality? Figure out how to set it up. Encounter a bug or issue? Troubleshoot and fix it. Functionality that you want doesn’t exist? Time to program it yourself.
You can also start customizing (ricing) your system as you wish. Take a look at unixporn style communities for inspiration and advice.