I am a German undergrad Math student (3rd year) at the university of Munich and I would classify our courses as relatively hard compared to what I have heard from other (German, but also some other Country's) universities.
During the terms, I really dedicate almost all of my free time to studying and Math itself because I really enjoy it and love learning new stuff. Yet, I really struggle at exams. I am always able to pass the exams by doing the standard exercises, but once it gets to tasks where you have to have the right ideas and think a little bit more I am unable to have a clear head and almost never get a REALLY good grade. My grades are almost always around B+ to B- (if correctly translated), but never an A or even A+, since there's always some exercises that I can't solve. I start feeling like I am either studying the wrong way or I am simply too "stupid" to do some harder exercises.
Whenever I talk to graduate or PhD students or even professors, they always tell me that they have been straight A+ students and I've never met one who was just an average or maybe a little bit above average student.
So my question: Is the excuse "I am just bad exams" a legit one and if not, how can I work on it? I don't think that I don't study enough, it's actually not really possible to dedicate more time to be honest. I would really love to stay in the academic field but I am afraid I am not the right type of person to work on higher mathematics.