Atmospheric neutrinos have played a crucial role in discovering neutrino oscillations, the only evidence of non-zero neutrino masses. Even now, they contribute significantly to our understanding of neutrino oscillations and mixing in the lepton sector. This talk analyzes the expected sensitivity of current and near-future water(ice)-Cherenkov atmospheric neutrino experiments. In this first in-depth combined atmospheric neutrino analysis, we carefully review the synergies and features of Super-Kamiokande, IceCube-Upgrade, and ORCA to examine the potential of joint analysis. By a detailed study of the current shared systematic uncertainties arising from the shared flux and neutrino-water interactions, and the systematic uncertainties of each experiment, we probe that the octant of $\theta_{23}$ can be resolved at 99\% C.L. and the neutrino mass ordering above $5\sigma$ by 2030. Additionally, we assess the capability to constraint $\theta_{13}$ and the CP-violating phase ($\delta_{CP}$) in the leptonic sector providing vital information for next-generation neutrino oscillation experiments.