Moving to german city to research study options, please advice

Hello, i'm currently preparing for a trip to germany with a Working Holiday visa. I want to look for study opportunities by going directly to the universities. This is because I have three paths in mind and want to find a university which will serve any of these (they are related to cognitive science, business informatics and embedded systems).

Considering this and the fact that I would like to be in a city with opportunities for an imperfect C1 german speaker, either mini jobs or more stable jobs.

Other interests are to do walkabouts and sightseeing, enjoy some concerts from time to time or to have some smaller music places nearby and to have access to a good public library.

Cities that i have in mind currently (because they have relevant study programs) are: Saarbrucken, Darmstadt, Konstanz, Passau, Kaiserslautern, Karlsruhe, Osnabruck, Ulm, Bamberg, Essen, Koblenz.

Can you advice on the better options considering the opportunities to build work connections in these fields and ideally maintain some stability in employment while i study? (doesn't matter if i have to be a waiter, just that i can rely on that job well).

Most important to me is which ones of these should i leave as last option?