Learned a lot and finally rooted.
This was an absolute challenge for my skills, and sometimes beyond. Thank you for the nudges to @Adam2019 and @kareem. Thank you to @gioo and cneeliz; very nice work!
The slight instability of the box is - somehow - reflecting a real life situation. You are sending a payload and nothing happens. Is it a mistake in the payload or the wrong payload at all … or do you have to calm down and wait a bit.