Well, to be fair, the guys who did Operation Valkyrie WERE German soldiers/officers, so some German soldiers/officers DID try to pull off killing Hitler.
Besides, when that young German Jewish kid tried to shoot Hitler during the 1930s, he ultimately failed, so it’s unlikely a German soldier would have been able to do the same thing (especially not after Hitler forced a loyalty oath to him alone to even JOIN the military at all, and that’s not even getting into the Hitler Youth where most of the kids didn’t even have a choice but to enter it.).
Any German officer standing two feet from Hitler prior to July 1944 could have blown his brains out.