We present a comprehensive investigation into the phenomenological consequences of axionlike particle (ALP) mediated dark matter (DM) on the structure of neutron stars (NSs). Our analysis is grounded in a well-established relativistic mean-field framework, featuring nonlinear mesonic self-interactions constrained by nuclear physics data and modern astrophysical observations. We systematically explore the DM parameter space, spanning DM particle masses $m_{\chi }\in [0,1000]\mathrm{GeV}$ and DM fermi momenta $q_f\in [0,0.06]\mathrm{GeV}$, by generating a vast ensemble of over 30,000 equations of state (EoSs). This analysis is carried out using two representative hadronic EoSs, a stiff one (EoS1) and a soft one (EoS18), with the explicit inclusion of the crustal EoS to properly account for the low-density regime of NSs. Employing a multitiered statistical filtering scheme, combining voting, likelihood, and kernel density estimation scores, we apply stringent constraints from a suite of multimessenger observations, including radio and x-ray pulsars, GW170817, and low-mass compact object HESS J1731-347, revealing that models satisfying the PSR J0614-3329 radius bound inherently comply with the HESS constraints, positioning ALP-mediated DM as a viable candidate for explaining low-mass compact objects while still supporting $2M_{\odot }$ NSs. For the stiff EoS, we obtain a lower bound of $m_{\chi }\gtrsim 43\mathrm{GeV}$, with score-weighted posteriors favoring $q_f=0.034_{-0.012}^{+0.020}$ and a broad allowed DM mass range $m\chi \in [101,949]\mathrm{GeV}$ (median $\sim 466\mathrm{GeV}$). In contrast, the soft EoS yields no strict lower bound on $m_{\chi }$, although scenarios with simultaneously large $m_{\chi }$ and $q_f$ are strongly disfavored. We developed a high-precision supervised interpolation model using AutoGluon to infer DM parameters from reconstructed NS mass-radius curves, achieving $R^2>0.998$. Feature-importance analysis indicates that the DM mass $m_{\chi }$ is mainly constrained by global shape indicators such as the radius ratio $R_{1.6}/R_{1.4}$, whereas the Fermi momentum $q_f$ is primarily determined by the tidal deformability ${\mathrm{\Lambda }}_{1.4}$.

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• Nuclear astrophysics
• Nuclear matter in neutron stars