To handle multiple messages efficiently in Kafka and MongoDB, you can use bulkWrite for batched updates and implement concurrency for processing messages in parallel.

1. Use bulkWrite for batching updates: Instead of calling updateOne for each message, aggregate multiple updates into a bulk operation

2. Increase concurrency for message processing: Use Promise.all or similar concurrency control (like async and await in batches) to allow parallel processing of messages.

This way, you can reduce the time spent on DB operations by processing in batches and improving throughput. I've attached screenshot also for code wise understanding

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