I actually asked a bottom friend about this and he says anal fissures are not cute at all and he wouldn't even be able to have a crap never mind "power bottom" his way through a torn and bleeding ass. It rules you out of bottoming for several weeks or months as the area needs to heal otherwise there is a risk of infection or chronic symptoms that would require corrective surgery. But straight female BL authors love their bottoms to have leaking and bleeding hole with no rest or recovery in sight.
The MC has a parasocial obsession with him - she loves the idea of the child actor she built an imaginary emotional connection with when she was lonely. Meanwhile, he's anxiously attached to his BFF and puts her on a pedestal as the person who rescued him. Her fixation makes her happy just to be in his orbit, while his fixation on his BFF makes him view the MC as an intruder into his social space.
I don’t think either of them are horrible people as of now. They’re just two weird, obsessive people who are attached to what others represent emotionally rather than fully seeing them as individuals.
I get why some question how romance can develop from this setup, but I’m excited for the post timeskip arc. Their psychological dynamics already lay a lot of groundwork for a genuine connection and eventual mutual pining to develop.