We present recent measurements of hadronic $B$ meson decays produced in electron-positron collisions at the $\Upsilon(4S)$ resonance collected between 2019 and 2022 with the Belle II detector. We show measurements of $B\to D^{(*)}KK_{S}^0$ decays including the first observation of three modes. Furthermore, we report on new results to determine the quark-mixing parameter $\phi_3/\gamma$, performed on a combination of Belle and Belle II data. Measurements of $B\to \rho \rho$ and $B\to \pi \pi$ are presented which serve as input for the determination of $\phi_2/\alpha$. Finally, determinations of branching fractions and direct $CP$-violating asymmetries of $B\to K\pi$ modes are shown to perform a direct test of the Standard Model via the $K\pi$ isospin sum rule.