Think about it this way, there are two types of smart: book smart and having logic/common sense. Are you fairly adequate in each of these? If so, you probly are just fine.
Its hard for people online who don't know you to answer that, but good luck.
We've no idea whether you are smart or not and no idea whether you will pass the 5 x Highers or not.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.