Uh, that’s not really it. Complexes are a series of exercises done using the same piece of equipment and the same load for each lift, but it’s not just one rep of each movement.
It’d be something more like using grabbing a 95-pound bar and doing 5 deadlifts then right into 5 snatches then right into 5 presses then right into 5 squats… that’s one set.(but that example a pretty funky complex with poor exercise setup.)
A giant set would be similar-but-different in that each exercise is treated individually and uses its own weight and/or a different equipment. Like, deadlift 225x5, then snatch 155x5, dumbbell press 60x5, hack squat 230x5.
Tons of coaches have articles talk about complexes, what they are, and how to program them:
Wil Fleming, again
But yeah, complexes are ball-busters for conditioning. If you’re self-conscious about collapsing in a sweaty, panting heap after using “only” 45-65 pounds, reconsider. A while back, I ran Cosgrove’s complexes for fat loss. Last set starts around 10:05…