<p>The remarkable capacity of bound states in the continuum (BICs) to confine light and enhance light–matter interactions renders them highly promising for advanced photonic applications. In this work, we propose two asymmetric strategies for realizing high-quality quasi-BICs in bulk tungsten disulfide (WS₂) metasurfaces: one employing a circular air hole and the other utilizing an asymmetric lateral shift of a single nanorod within the unit cell. The reflectance spectra of these asymmetric metasurfaces exhibit tunable quasi-BIC resonances whose quality (Q) factors depend strongly on the asymmetry parameter, achieving values as high as 2 × 10⁵ at asymmetry levels of 0.35% and 2.22% for the air-hole and shifted-nanorod designs, respectively. We further investigate the influence of an engineered substrate, comprising a thin silicon (Si) layer embedded in silicon dioxide (SiO₂). Varying the vertical separation between the metasurface and the Si layer produces a monotonic shift in the excitonic resonance wavelength, while the quasi-BIC resonance wavelength undergoes a sinusoidal-like modulation, which is accurately captured by analytical models. By fitting the resonances to a Fano lineshape, we analyze the modulation of key Fano parameters by the Si-layer position. Finally, we demonstrate that this engineered substrate stabilizes the quasi-BIC resonance wavelength against variations in the air-hole radius—a crucial step toward practical device implementation. Our results establish a robust platform for achieving tunable, high-Q, and spectrally stable resonances in transition metal dichalcogenide (TMDC)-based metasurfaces, with promising implications for nonlinear optics, sensing, and integrated photonic technologies. </p>