  Greenberger-Horne-Zeilinger (GHZ) states, as maximally entangled
Schr\"{o}dinger cat states, play vital roles in the foundations of quantum
physics and technology, but creating and preserving these fragile states pose
tremendous challenges. Discrete time crystals (DTCs), originally aimed at
exploring exotic nonequilibrium quantum matters, have raised significant
scientific interest, but whether this brilliant concept can lead to true
applications remains unclear. Here we propose an efficient protocol suitable
for two-dimensional quantum processors, and by employing sequences of
high-fidelity quantum gates, we achieve genuine GHZ entanglement at the
intermediate scale with up to 60 superconducting qubits. More importantly, we
take a new perspective on DTC by deterministically engineering pairwise cat
eigenstates as quantum many-body scars, which shield the GHZ states from
generic perturbations and enable dynamical switching during the state
evolution. Our results not only nail down a direct application of DTC, but also
establish engineerable many-body systems far from equilibrium as a versatile
platform to protect and steer fragile but intriguing quantum entanglement.
