Compensators are different from ports in that;
Ports only vent gases out of the barrel to create down force, whereas comps are attachments added usually to the muzzle and have at least one baffle or a series of baffles that are more or less perpendicular to the axis of the bore through which the bullet passes after exiting the muzzle. The expanding gases slam into these baffles just behind the bullet as it transitions the comp and are then vented upwards, pushing the muzzle forward and down to compensate for recoil (flip). I have both ports and compensators on my IPSC race guns. Best of both worlds.
Yes, they do require hotter loads to work but it's more about gas volume than pressure, so slower powders are the norm to increase the size of the gas column. They do also add weight which may indeed soak up some of the recoil, but with weight comes momentum and inertia, which has to be overcome as the muzzle is lifting and settling. Too much weight added to the front of a gun is not a good thing if speed of recovery is important. That is why most modern comps are as light as possible.