I would love to have the physique Pacquiao or Marquez had during their third and fourth fights. I will absolutely not be able to drop weight as much as they have. Iirc, they were at 150 during those fights? I currently stand at 158 with four-pack. If I can get to 155-160 with a six-pack, I would be a very happy man.
But it needs to be stated that bodybuilding is a sport, just like how combat sports are... a sport. Getting the jacked, muscular body-shape requires sacrifices that a professional boxer cannot achieve. Professional boxers frequently fight at weights far, far below their actual natural weight. Good luck getting a jacked body when you're fighting at weights 10-30lb lower than you're supposed to.
I'll return to Marquez. I am the exact same height as he is, and I feel most natural when I'm sitting at 155-165. The man fought at weights ranging from 120-140 for most of his professional career. I simply cannot imagine looking muscular at that weight. Hell, I cannot imagine myself fighting a 12 round fight at that weight.
But that's boxing. Professional boxing requires tremendous sacrifice, and that is largely incompatible with body-building or having an aesthetically pleasing body.
Grappling, on the other hand, is a different story. Making weight is far less punishing for grappling (many contests and tournaments that I know of don't even have weight requirements), and as such you have people who look far more like they're supposed to for an athlete of their caliber and size.
Not to mention, having a 300lb bench or a 400lb squat won't make you punch faster in the slightest. Having a 300lb bench does give you the power to push off that 170lb guy lying on top of you when compared to a 200lb bench.
So, if you want to having an aesthetically pleasing body while doing some combat sport, look into either MMA or pure grappling, not boxing.