The prey mechanic is pretty easy once you look into a little closer.

First up, for the bulk of the encounter prey is entirely predictable to the point where you can time it to within a few seconds accuracy. Record yourself if possible, jot down the rotation for the first two main phases and stick that to the side of your monitor or tv whilst you carry on learning the encounter.

For phase 1, it's easiest for the SCH to handle Prey with Adloq, you need to be alert and able to target people quickly for this as not being able to will pretty much guarantee a wipe in phase 3.

Initially, the double prey of the add phase feels like the hardest part of the mechanic to deal with, but frankly, it's actually the easiest. Have the WHM pop POM and Stoneskin both healers as well as all of the DPS, if you can time it so you start doing this a second or two before the adds pop, all the better as the first double prey will come right as you finish up the stone skins. As long as the tanks position the adds correctly and don't get the raid AoE'd these stone skins coupled with a pre succor will safely absorb two prey hits without issue. More gets a little risky so it's better to re stoneskin the target after the prey hit to be safe particularly on the second add phase.

Finally, phase 3 consists of a 2 move combo followed by ~20 seconds of fluff attacks, prey only ever gets used alongside critical rip as a potential 'fluff' attack. It's easiest if the WHM focuses on dealing with the critical rip hit on the tank whilst the SCH Adloq's the prey target, if you're struggling to spot the prey quick enough, remember that you can focus target the boss and watch for the critical rip cast at this point.

Good luck, and work on your targeting speed and accuracy!