Signals and Telecommunication Journal Duong Van Hieu 15 2 2026 https://doi.org/10.6025/stj/2026/15/2/88-110 https://www.dline.info/stj/fulltext/v15n2/stjv15n2_3.pdf The evolution of sixth generation (6G) networks relies heavily on Terahertz (THz) communications and Cloud-IoT architectures, which introduce complex trade-offs between communication quality, network stability, and security overhead. Evaluating these heterogeneous environments requires comprehensive frameworks capable of handling multiple, often conflicting performance criteria. This study proposes a novel hybrid Multi Criteria Decision-Making (MCDM) framework to evaluate THz enabled Cloud IoT networks. Using a comprehensive dataset of 4,000 observations encompassing environmental, communication, and blockchain-based security metrics, we integrate both subjective and objective weighting mechanisms. Specifically, the Analytic Hierarchy Process (AHP), Entropy Weight Method (EWM), and CRITIC are utilized to derive criterion weights, which are subsequently applied in TOPSIS and VIKOR ranking algorithms. The results signal a high degree of concordance among the weighting schemes. AHP and CRITIC prioritize core communication metrics like signal strength and bandwidth, while EWM highlights the critical statistical variability of blockchain validation latency. Extensive sensitivity analyses confirm the framework’s structural robustness against weight perturbations. Furthermore, TOPSIS and VIKOR rankings consistently identify optimal network configurations that effectively balance high capacity links with low latency and robust trust scores. These findings emphasize that optimizing next generation systems requires a holistic approach to dynamically adapt to multi dimensional constraints. Ultimately, this hybrid MCDM approach offers a rigorous, multi perspective decision support tool for network architects, ensuring the optimal deployment of intelligent, secure, and high performance 6G THz Cloud IoT environments.