The advent of sixth generation of cellular network technology (6G) technology fosters Healthcare 4.0, including advanced predictive diagnostics and elevated patient convenience. With the resource-constrained Internet of Things (IoTs), Electronic Health Records (EHR) are mandatory for Healthcare 4.0 patients. Transparency in transactions encourages the utility of decentralized architecture for attaining security and privacy in Healthcare 4.0 by using the IOTA Tangle. Limited IoTs demand storage efficiency while achieving security and privacy. The Healthcare 4.0 use case diminishes storage efficiency in IoTs as the conventional Merkle Tree implementation directs super-exponential growth. We exposition the growth rate of the Merkle tree for a use case adhering to Healthcare 4.0 and identify the dynamic growth on the left side with varying vertical levels. We introduce pruning on the dynamic side to balance the growing tail of the tree, presenting the dynamic balancing hybrid Merkle tree (DBHMT). We analyze its morphological and security characteristics and lay down closed-form expressions. As there is an optimal value between security and storage efficiency, we formulate the optimization problem for reducing the storage cost that is NP-Hard and non-convex in nature, so we apply the gradient descendant optimization algorithm by incorporating Adam's update mechanism to find the optimal pruning factor. We evaluate the behaviour of Merkle Tree, DBHMT without pruning and DBHMT in IOTA Tangle for 1 million transactions and found that DBHMT reduces the storage cost by the ratio of four in comparison with the conventional Merkle tree, and the trend continues for growing transactions. Finally, we discuss future research directions by examining prevailing problems.