This whole part seems overly complicated to me (it already was in the original implementation). But it's probably not the point for premature optimization here. Could you add a TODO: revise parameter lookup here so we can track what parameters we need to test/improve in the future?

Totally agreed with this point - I added the TODO but I still believe that we should use "." as a delimiter, for example, please take a look at how Navigation2 loads the parameters yaml - cpp

I think the yaml you linked doesn't belong to the cpp file. What they did is use dynamic_reconfigure to generate the parameters: https://github.com/ros-planning/navigation2/blob/6bfa8c48ea0291fff540eb7aead6e5e511130bd7/nav2_costmap_2d/cfg/ObstaclePlugin.cfg. Normal parameters use forward slashes as namespace separators, at least I didn't find anything that supports something else: https://design.ros2.org/articles/ros_parameters.html https://design.ros2.org/articles/topic_and_service_names.html.