Alternate approach - eliminate by capture mechanism:
Cockroaches are largely scavenging omnivores, not specialised predators relying on mechanical restraint of prey.
Grasshoppers are herbivorous, feeding on plant tissue rather than capturing live prey.
Mantis species do use raptorial forelegs to seize prey, but they grip with their front legs rather than relying purely on sheer body strength before shredding with mandibles - so this does not match "restrains by sheer mechanical strength" as precisely.
The remaining option, Predatory mite, physically overpowers and pins prey using strong claws and body strength before tearing it apart with its chelicerae, matching the description given in the question.