I'm trying to create a simple 1 DOF arm and perform position close-loop control by changing the motor (joint) velocity and reading the position

My starting point is:

ros2 launch ros_gz_sim_demos joint_states.launch.py

this example uses the gazebo plugin:

<plugin filename="ignition-gazebo-joint-state-publisher-system" name="ignition::gazebo::systems::JointStatePublisher"/>

I modified the launch file, so the rosgzbridge is bridging /joint_states topic both ways I don't know how to change the velocity or effort of the joint, I tried this with no luck:

ros2 topic pub /joint_states sensor_msgs/msg/JointState "{velocity:[0.0, 5.0, 0.0]}"
ros2 topic pub /joint_states sensor_msgs/msg/JointState "{effort:[0.0, 5.0, 0.0]}"
ros2 topic pub /joint_states sensor_msgs/msg/JointState "{position:[0.0, 5.0, 0.0]}"

What can I do to interact with the joint from ROS2? or even with gazebo, as i don't see any relevant topic when I list the available topics with

ign topic -l

I saw there is another gazebo plugin "ignition::gazebo::systems::JointController" but couldn't make it work ether