Hi
So what you need to do is rather than just say what book you have read, you need to make a comment on it. So for example with Cheng’s “Beyond infinity” , you don’t need to describe the book, because they should know about it and if they don’t they can look it up. Don’t waste characters. So something like :
Reading Cheng’s”Beyond infinity” made me realise….. or whatever interesting comment you can make about your opinion on the book.
Again with the university program that you were involved in, you need to spend less time descrbing what you did and more time describing why you found it interesting and what you took away from it.
And so on, for everything you have done or read, dont describe it in detail. The maths and physics experts who read your paper will know , it is fine to assume that they have that knowledge, but you need to give opinions and comment on everything that you have done.
Otherwise your teacher is right, you are just listing books you have read and things you have done without giving any opinions or reflections on them.
Good luck 😊