A Dunkleosteus does not have any guns to shoot with, it rams into it's enemies :D I do not know much about them, but I don't think they are good for taking down pirate OPS. They are better used to destroy other players stations and moons with. You need a space station with gravity gun, from human's moon to properly take down planetary defense and shields.
https://prnt.sc/ra1bmy ,
https://prnt.sc/ra1bso