With technological advancement and the deepening pursuit of carbon peaking and carbon neutrality, renewable energy sources such as wind and solar power have evolved from being supplementary into mainstays of the energy system, poised to serve as its very backbone. However, wind and solar energy sources are inherently intermittent, fluctuating, and stochastic. Therefore, how to transform these energy into controllable, flexible resources has emerged as a pressing scientific and engineering challenge. This study reviews the challenges confronting the high-level development and utilization of wind and solar renewables, sets forth pathways and key strategies for converting their intermittency, volatility, and randomness into flexibility, and offers concrete policy recommendations. The study proposes that, by adhering to the overarching approach of strengthening coordinated interaction among "source, grid, load, and storage," and by advancing renewable energy development alongside conventional power source retrofitting, enhancing the grid's capacity for resource allocation, improving precision monitoring and demand response of diversified loads, and establishing a hierarchical, diversified energy storage regulation system, the intrinsic characteristics of wind and solar energy can be fundamentally reshaped, enabling their high-level exploitation. The study further recommends refining relevant laws, regulations, and policy frameworks; optimizing support policies for distributed renewable energy; enhancing zero-carbon benefits from centralized renewable development; deepening power sector reforms; deploying grid infrastructure with moderate foresight; unlocking the potentials of various flexibility resources; continuously accelerating innovation in key renewable technologies; and strengthening policy coordination and oversight, so as to drive the high-quality development and utilization of wind and solar renewables and advance the goals of carbon peaking, carbon neutrality, and building an energy-strong nation.