Act as a Principal Software Architect. Design a high-level architecture for a real-time collaborative editing application similar to Google Docs, specifically optimized to handle 10 million concurrent active users. Your design must address the following: 1) Data consistency algorithms (compare OT vs CRDTs and justify your choice), 2) Database sharding strategy to minimize latency, 3) Conflict resolution mechanisms for concurrent edits, 4) Load balancing approach for WebSocket connections, and 5) Caching layers for document snapshots. Provide a written explanation of the components and their interactions, avoiding code blocks.