<p>This review provides a comprehensive and comparative assessment of biomass conversion technologies for renewable energy generation and their role in achieving net-zero carbon targets. Unlike previous studies that focus on individual pathways, this article uniquely integrates physicochemical, thermochemical, and biochemical routes, while also highlighting the emerging potential of hybrid systems and AL/MI-driven optimization. A quantitative comparison demonstrates that hybrid bioenergy systems can reduce overall costs by 15–37% and lower greenhouse gas emissions by 12–30%, offering significant environmental and economic advantages. Recent advancements in pretreatment, catalytic processes nanotechnology, and bioreactor design have further improved the accessibility and conversion efficiency of cellulose and hemicellulose, enabling higher yields of biofuels and bioproducts. Thermochemical approaches are recognized for their efficiency, biochemical methods for their eco-friendliness, and physicochemical techniques for their simplicity, while each still faces challenges of high capital cost, feedstock variability, and scalability. The novelty of this review lies in synthesizing these diverse technologies with techno-economic and environmental perspectives, thereby outlining a roadmap for sustainable biomass utilization. Future research is recommended to advance hybrid models, nanocatalyst development, and digital optimization tools, ensuring the large-scale affordability and integration of biomass systems into the global bioeconomy.</p>