Recent Belle II results on BSM physics

We report on recent results obtained by the Belle II experiment related to searches for beyond-the-standard-model physics. The $B$ meson decay data sample used corresponds to an integrated luminosity of $L=189$ fb${}^{-1}$. In recent years, discrepancies from standard-model predictions, which suggest violation of lepton-flavor universality, have emerged in multiple measurements of $B$-meson decays. In this document two analyses aimed to search for violation of the light-lepton universality are reported: the inclusive $R(X_{e\mathrm{/}\mu })$ measurement and an angular analysis of the $B^0\to D^{\ast -}{l}^{+}{\nu }_l$, with $l=e,\mu$, decays. In addition, beyond-the-standard-model physics can manifests itself with the production of new particles. The search for a long-lived spin-0 particle in $b\to s$ transitions, and its interpretation in two dark sector models, is reported.