Ok. Well, you can try, but even with a great profile the probability of getting accepted when applying to only one university is really low.
I checked Mannheim's website, it seems that in 2017 it got 19 students for 7 programs. That seems to mean that each program, like Management, would have about 2 or 3 students each year, the same numbers I've seen here in the US.
With the information you have provided here, I don't think Mannheim will have trouble finding 2 or 3 applicants with profiles stronger than yours. And sometimes you are not really competing for 2 or 3 spots, because each program has different divisions. In my field, for example, the expectation is 2 new students for the Marketing PhD program each year, being 1 in consumer behavior and 1 in quantitative marketing. You really have to be among the best of the best, because they accept only 1 for a given research interest.
If you really want to go for a PhD, I suggest trying to strengthen your profile first and maybe try next year. Get a great GMAT score, get some research experience, then maybe you have a fighting chance.