Where are lambda logs?

Lambda does write to CWLogs with in seconds.

Are you seeing a Log Group for you lambda? If so are there any Log Streams in that log group. Using the Monitoring console is probably the easiest way to get to the Log group for a Lambda: https://docs.aws.amazon.com/lambda/latest/dg/monitoring-functions-logs.html

Also be aware that a new log stream will be created every time your Lambda moves to a new underlying container, so if you are viewing one stream and not seeing new statements, they may be going into a new stream in that Lambda log group.