Can you describe how the client and server are connected? i.e. is this on your laptop connecting to a Docker container? Are you in a particular cloud provider?
Typically a timeout at this early stage is caused by some networking issue in between the client and server rather than a bug or performance issue.
You can also try using the sdk doctor to get more connection diagnostics:
And there is some good documentation in the Python SDK for error handling and troubleshooting:
Diagnosing and preventing Network Problems with Health Check | Couchbase Docs and Handling Errors | Couchbase Docs
(also note that version 4 of the Python SDK is available now, I don’t have any reason to suspect that upgrading would resolve the issue you’re having, but good to be aware of the latest version 
)