Improve Navigation2 Launch Reliability? Frequent smoother_server timeout

[slowrunner]

How can I improve the reliability of my nav2 navigation launches?

I have to launch nav2 several times before seeing a successful bringup with global and local costmap ready for an initial pose and navigation goal.

The failed launch always contains the following warning:

[planner_server-3] [WARN] [1740264294.156083284] [planner_server.rclcpp]: failed to send response to /planner_server/change_state (timeout): client will not receive response, at ./src/rmw_response.cpp:153, at ./src/rcl/service.c:400

ROS 2: Jazzy
OS: Ubuntu 24.02
Processor: Raspberry Pi 5 8GB
Platform: Turtlebot4

I am running everything on-board. Rviz2 visualization is remote.

I have submitted an issue on the Turtlebot4 repo with logs and more information:
Frequent Nav2 smoother_server timeout (and no global costmap) on repeated navigation launches #555

Processor average load is less than 100%, with some 1 minute loads in the 4 to 6 range briefly during launch.

When the launch succeeds, navigation proceeds smoothly with no issues with average load between 2 and 3 (50-75% of processor).