You can skip almost 2 playthroughs entirely, but only if you're double-dipping and playing the Vita version as well, which you get for free if you buy the PS4 version.
I played Normal on PS4, then Normal, Advanced, and Expert on the Vita. Right before the final mission on Expert on Vita, I quit, then loaded the save on PS4. I backed up my save to USB, then quit the PS4. Finished Expert on Vita, and reloaded on PS4. It wanted to start a new game, so I quit again, overwrote the save with the one from USB, and when prompted, told it to take the local file over the server version.
That put me on the final mission on Expert, and beating that popped the trophy, meaning I only had to play Normal + the final mission on Expert. I suspect the trophy assumes you couldn't have gotten to Expert without first finishing Normal + Advanced, and if true, you could probably get all the way to the end on Vita without having played on PS4 at all, do this USB trick, and only have to play a single mission, then mop up the other trophies.