Information Asymmetry Across Blockchain Architectures: A Systematic Review and Taxonomy of DEX-based AMMs

Decentralized Exchanges based Automated Market Makers have become dominant in DeFi, yet their transparency creates fundamental information asymmetry exploitable as Maximal Extractable Value. This asymmetry, manifests differently across blockchain architectures. A PRISMA 2020 systematic review of 119 studies from 2018-2026 to map up how transaction Exposure, Order-Flow Leakage, and Execution Control occur in Mempool L1s, Mempool-less L1s, and Sequencer Based-Rollup L2s. It was found that removing public mempools does not eliminate asymmetry but shifts it to scheduled leaders responsible for block production, while centralized sequencers in rollups represent the most severe risk, granting single entities both ordering, execution and extraction power. Mitigations such as private RPCs, encrypted mempools, and proposer-builder separation address one axis while worsening another. A taxonomy that shows that there is no "MEV-free" architecture but only trade-offs was proposed. It was concluded that since information asymmetry is blockchain architectural issue there is still gap into process, academics and developers should study deep into the process to proffer mitigation to this, right from the point of signing the contract before confirmation.