<p>Two-dimensional MA₂Z₄ (M = Mo, W, A = Si, Ge, and Z = N, P, As) materials have recently emerged as a versatile family of layered materials whose structural and electronic properties are tunable by chemical engineering and strain-induced variations. Here, we investigate the lattice thermal transport and the sliding-dependent interfacial potential energy surfaces (PES) of Janus MoSiGeN₄ bilayers with different interface compositions and stacking configurations. Our calculations reveal that while harmonic phonon dispersions remain nearly unchanged across different interfaces, the curvature of the interfacial PES governs the anharmonic response and thereby enhances the scattering of low-frequency acoustic phonons. In particular, the chemically asymmetric Si-Ge interface introduces stacking-dependent PES landscapes and enhances the scattering of low-frequency acoustic phonons and leads to a 10% suppression of in-plane lattice thermal conductivity. These results establish a microscopic connection between interfacial energy landscapes and anharmonic phonon scattering, demonstrating that sliding-induced modifications of the interfacial PES provide an effective route for tuning phonon transport in two-dimensional layered materials.</p>