Multiple SQS queue to same Lambda

Every time you configure a queue as an event source for a Lambda function, we create pollers to read from the queue and invoke the function when there are messages. If you configure two queues with the same function, we will create two sets of pollers to read from these queues and invoke the function. Each one of these pollers will scale independently so you will need to have enough Lambda concurrency in your account to accommodate for the higher concurrency.

The Behavior is described in the "Scaling and Processing" Section.
It describes that you have at a max 1k processes reading from a Queue and hand over the Batches to your function. With more than one Queue feeding the function you will have more parallel Lambda executions, so take care of your Lambda Limits.