  Eigenstate Thermalization Hypothesis(ETH) has played a pivotal role in
understanding ergodicity and its breaking in isolated quantum many-body
systems. Recent experiment on 51-atom Rydberg quantum simulator and subsequent
theoretical analysis have shown that hardcore kinetic constraint can lead to
weak ergodicity breaking. In this work, we demonstrate, using 1d spin-1 PXP
chains, that miscellaneous type of ergodicity can be realized by adjusting the
hardcore constraints between different components of nearest neighbor spins.
This includes ETH violation due to emergent shattering of Hilbert space into
exponentially many subsectors of various sizes, a novel form of
non-integrability with an extensive number of local conserved quantities and
strong ergodicity. We analyze these different forms of ergodicity and study
their impact on the non-equilibrium dynamics of a Z2 initial state. We use
forward scattering approximation (FSA) to understand the amount of
Z2-oscillation present in these models. Our work shows that not only ergodicity
breaking but an appropriate choice of constraints can lead to restoration of
ergodicity as well.
