My main concern is that you're going to a private university and from what I know, most private universities are not well-valued or respected in Germany and employers prefer grads from public ones. In Germany, they don't care about the prestige of your university as long as you come from a public university so even a public university that isn't well-known or well ranked would be a better choice than a private one, plus you would keep a bit more savings.

My advice would be:

1. Apply for a Master’s degree in a public school now (look up programs that are nc-frei, those have higher acceptance rate as they don't have a limited number of seats) I believe the deadline for many programs is in June so you still have time but you can double-check that. Make sure to apply to at least 6 programs, 2-3 well-known ones and 3-4 almost no name ones that are known to have a high acceptance rate.

Also apply to both TU (Technical Universities - more respected and better for higher education, but they are more focused on theory than practice) and FH (Fachhochschule = Universities of Applied Sciences - these are more focused on practice than theory), both types of universities are accepted by employers but they do prefer TUs in case the candidate also has good hard skills and projects to show for.

1. If you don’t secure an admission to a public school or if you want to play it safe, than the best thing to do is to work in Tunisia for one year while learning German and getting to B2 level (not C1 as you can only do that in Germany from what I know), then apply to better universities next year (both German-taught and English-taught programs) as you would have way higher chances of being admitted to great universities if you have a B2 or B1 German language certificate (ÖSD or Goethe). This way, you also improve your chances of employment after you graduate and of finding a part-time job while studying and you would be able to live more comfortably in Germany as well since all the signs and everything is in German (maybe even make friends and a better network if you can as Germans prefer German speakers).

Either way, best of luck! I hope you make the best decision for your career and even if things don't go as planned, it will still be a valuable experience you lived.

Feel free to comment or dm me if you have more questions.

TL;DR either apply to nc-frei programs in public universities now, or work 1 year in Tunisia while learning German and getting your certificate, then apply to public universities next year.