Metal-doped borophenes offer a versatile platform for realizing topological superconductivity and investigating exotic quantum states. In this study, through extensive structural searches, we identify the $t\text{-Be}{\mathrm{B}}_3$ monolayer and its stacked bilayer as the lowest-energy configurations within their respective layered systems. Compared to the monolayer, the ${\mathrm{AB}}^{\prime \prime }$-stacked bilayer forms interlayer Be-B covalent bonds that not only enhance thermodynamic stability but also drive a topological phase transition—resulting in the emergence of Dirac points and topological surface states near the Fermi level. Remarkably, the $p_z$ electrons localized on the interlayer Be-B bonds induce van Hove singularities and a flat band, which strongly couple to out-of-plane phonon modes. This leads to a significant enhancement in electron-phonon coupling (EPC) strength—from 0.51 in the $t{\text{-BeB}}_3$ monolayer to 0.85 in the bilayer—and yields a threefold increase in the superconducting critical temperature ($T_c$) from 10.3 to 30.2 K. These results highlight the pivotal role of interlayer bonding in tuning the electronic structure and EPC in borophene-based materials, offering a promising pathway toward the design of high-$T_c$ topological superconductors.

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• Density of states
• Edge states
• Electronic structure
• Flat bands
• Spin-orbit coupling
• Topological materials
• Topological superconductors
• Bilayer films
• Monolayer films
• Density functional calculations