The exponential growth of intelligent devices within Internet of Things (IoT) networks has escalated the complexities associated with ensuring secure device communication. In response to these challenges within 5G-enabled IoT networks, this study introduces a multi-tiered blockchain security architecture, strategically designed to streamline implementation while concurrently fortifying network security measures. This architecture harnesses the capabilities of an adaptive clustering methodology rooted in Evolutionary Adaptive Swarm Intelligent Sparrow Search (EASISS), which efficiently organizes heterogeneous IoT networks.The process involves the meticulous selection of cluster heads (CH) responsible for overseeing localized authentication and permissions. This strategic allocation minimizes communication distances between CHs and IoT devices, effectively curtailing overhead and latency. Furthermore, the Network Efficient Whale Optimization (NEWO) algorithm is harnessed for managing network modifications, encompassing tasks like node addition, relocation, and deletion.Within this framework, a localized private blockchain structure plays a pivotal role, facilitating secure communication between cluster heads and base stations. This architecture substantiates enhanced security and trustworthiness through an integrated authentication mechanism.Simulation outcomes aptly illustrate the efficacy of the proposed clustering algorithm in comparison to existing methodologies. Notably, the lightweight blockchain approach championed in this study successfully strikes an optimal equilibrium between network latency and throughput, showcasing a distinct advantage over conventional global blockchain systems. Notably, the maximum transaction delay exhibited a rise when throughput reached 100 TPS, while the minimum latency consistently remained below the 1-second threshold.