I read the communist manifesto wanting it to turn me into a communist, wanting to learn about what the communist utopia looks like. I was disappointed on both things. It seems like the real communism/utopia for communists is the constant struggle for revolution and socialism.

I don't think that reading a book will necessarily radicalise you into thinking that way. I don't know what else needs to be there but I think you generally need to be open and in agreement with what is being said to follow it. Like it has to speak to you but that presupposes that you already agree with those viewpoints even if you couldn't quite articulate them.