how to deal with this prof when he gives you his lowest grade?
You should assume the grading is fair, unless there is a reason to believe otherwise. Based on your question and comments, I don't see any reason to believe that discrimination is involved.

You state that you did everything that was required, just like the other students. That doesn't mean you should get exactly the same grade as them. Perhaps your presentation was not as clear as the others or your project had some minor flaws. It is very hard for you to judge that yourself -- you are neither an expert like the professor is nor objective in self-evaluation.

You received a 92, which is below the class average of 94. To me, that still sounds like a good grade and you shouldn't be concerned. Trying to argue for every last point is not productive -- it's called grade grubbing.