We perform a systematic study of flavor-changing neutral currents (FCNCs) in the 331 model with right-handed neutrinos (331RHNs), analyzing constraints on the Z′ boson mass from K-, D-, Bd-, and Bs-meson oscillations. By explicitly incorporating scalar sector dynamics and quark rotation ambiguities \( \left({V}_L^{u,d}\right) \) , we demonstrate that Z′ mass limits depend critically on the parametrization of Cabibbo-Kobayashi-Maskawa (CKM) matrix factors. Three scenarios are explored: (i) \( {V}_L^u \) = \( {V}_{\textrm{CKM}}^{\dagger } \) (FCNCs restricted to D-mesons), (ii) \( {V}_L^d \) = VCKM (dominant Bs constraints), and (iii) a hybrid mixing pattern. Strikingly, scenario i) reduces the Z′ mass bound to \( {M}_{Z^{\prime }} \) ≳ 600 GeV — two orders of magnitude below literature values — by leveraging large experimental uncertainties in D- \( \overline{D} \) oscillations. Conversely, scenario ii) requires \( {M}_{Z^{\prime }} \) ≳ 165 TeV due to stringent Bs data. We further establish the alignment limit cos(ϕ + φ) = 0 for the SM-like Higgs, showing its viability depends on \( {V}_L^{u,d} \) configurations, with Bs systems enforcing |cos(ϕ + φ)| < 0.01 in down-sector FCNC scenarios. Our analysis reveals that strategic choices of quark mixing matrices can suppress FCNC visibility, reconciling the 331 framework with flavor data without ultra-heavy Z′ bosons. This work provides the first unified treatment of SM-like Higgs- and Z′-mediated FCNCs in 331 models, identifying viable parameter spaces for collider phenomenology.
