Mergers and acquisitions often leave organizations with multiple SIEM platforms, fragmented architectures, and inconsistent data policies that are costly and difficult to manage. A SIEM-agnostic Security Data Engine (SDE) can centralize log collection, consolidate historical data, and route current data to the right destinations during the transition. This approach reduces costs, avoids vendor lock-in, and ensures compliance while enabling a phased migration to a unified SIEM platform.