that’s indeed the cause of your problem.
The ZED ROS Wrapper publishes data following the ROS REP105 standard, so the full TF chain must be available:
base_link → […] →
The static TF transforms of the camera links are published by the
robot_state_publisher node that is started with the ZED launch files.
If that node is not running the TF chain is broken and the node waits for valid transforms for each frame that it received with a timeout of 0.1 sec.
That’s why you are getting this low topics rate. You must install the missing package in your docker image:
apt install ros-$ROS_DISTRO-robot-state-publisher