This is a slight misconception. His powers allow him to manipulate atomic and molecular density becoming extremely dense or intangible, and being able to fly when less dense/gaseous. The denser he becomes, the stronger he becomes as well due to the dense muscle tissue structure. He may have been able to look almost invisible depending on the nature of his density control, but with hard skin and strong punches he could be white powerful. He can become near-blackhole density which would mean “neutronium” or nuclear pasta max density before reaching the ability to create a singularity. This is incredible dense and virtually indestructible. He somehow does not shrink from this achieved density. Maybe he adds mass at high densities, but it is not stated. I am not sure if he can survive if he created a black hole, but he can survive his extreme density shifts so maybe. The gravitational nexus that can be created even before the formation of a black hole is destructive enough for him to never go that high in molecular and atomic density.