Condition for 144-hour visa-free transit

Hello,
I read that "Passengers should hold an onward ticket with a confirmed seat and date as well as a valid visa to a third country or region." I understand that the country of my departure flight into Shangai has to be different than the country of my arrival flight (leaving) from Shangai, right? Does it apply only to connection flights or also to the original origin & destination flights? Like in my case, I plan to leave and return to Luxembourg, but I will then take connection flights in different country/ies to and out of Shangai. Will I still be eligible?
Thanks a lot for confirming!