Vapor-phase deposition is crucial for scalable perovskite photovoltaics, yet precisely controlling organic-inorganic vapor-solid reactions to yield highly crystalline, phase-pure thin films remains a fundamental challenge. While close-spaced sublimation (CSS) provides an excellent platform for scalable manufacturing, its microstructural reliability is conventionally limited by decoupled nucleation and bulk phase conversion kinetics. Here, we elucidate the reaction kinetics governing CSS, identifying the total sublimation amount (TSA) as the defining parameter that dictates a diffusion-controlled, top-down phase evolution. We reveal a severe kinetic competition between the (100) and (111) crystallographic facets during growth: insufficient TSA leaves unreacted PbI2 at the buried interface, whereas excessive TSA drives disordered, (111)-dominant overgrowth. By rationally decoupling these kinetic stages via an in-situ atmosphere annealing (IAA) strategy, we selectively suppress the (111) facet and comprehensively eliminate basal PbI2, establishing a highly ordered (100) texture throughout the bulk. Consequently, the champion inverted (p-i-n) devices achieve efficiencies of 21.31% (0.04 cm²) and 18.35% (1.00 cm²). Demonstrating robust thermodynamic control, this approach delivers exceptional operational stability (retaining 90.4% efficiency over 1,000 h), and remarkable batch-to-batch reproducibility (1.68% relative standard deviation across 32 batches) providing a scalable, highly reproducible route for industrial-grade perovskite fabrication.