SageMaker Notebooks do not have an "Official" way for ssh connections, although it is possible to find instructions for it using ngrok.
Is it possible to use session manager instead? Although the SageMaker Notebook looks like an ec2 the arn does not starts in the same way, it has arn:aws:sagemaker
instead of arn:aws:ec2
.
I tried this via aws cli but I get An error occurred (TargetNotConnected) when calling the StartSession operation: