When we want to observe msg by rqt, the following log occurs and it cannot be observed on Topic Monitor.
$ rqt
[WARN] [1694593985.541597582] [rqt_gui_py_node_1735161]: New publisher discovered on topic '/to_linux', offering incompatible QoS. No messages will be received from it. Last incompatible policy: RELIABILITY

This is because the default QoS policy for rqt (and rviz) is set to RELIABILITY, maybe from Galactic.
ros-visualization/rqt#187
https://answers.ros.org/question/358669/problem-to-read-topics-with-sensorqos-in-rviz-and-rqt/
So, we need to implement the feature to select QoS policy to RELIABLE, or set the default to RELIABLE. Fortunately, embeddedRTPS offers BEST_EFFORT and RELIABLE as selectable QoS policies.
When we want to observe msg by rqt, the following log occurs and it cannot be observed on Topic Monitor.
This is because the default QoS policy for rqt (and rviz) is set to
RELIABILITY, maybe from Galactic.ros-visualization/rqt#187
https://answers.ros.org/question/358669/problem-to-read-topics-with-sensorqos-in-rviz-and-rqt/
So, we need to implement the feature to select QoS policy to RELIABLE, or set the default to RELIABLE. Fortunately, embeddedRTPS offers BEST_EFFORT and RELIABLE as selectable QoS policies.