Harris Dickinson goes out on a bit of a limb with this role - and generally pulls off a convincing effort as a sexually repressed/confused teenager who leads a triple life - with a straight girlfriend; with his macho homophobic mates and when he picks up men online - or on Coney Island pier - for casual sex. The story is nothing new, but this is an edgier and grittier rendition of the coming-out story. I have to say…