This has been solved in the comments by ekhumero, thank you ;)
I need to have my window stay on bottom.
There is the windowOnTop flag, as dicussed here (here using pyqt4, but it's an well enough example), but is there a way to achieve the exact opposite?
I'm using Linux (Manjaro) with X11, so I'll accept X11 specific answers too, if they work with pyqt5, cross plattform compatibillity is no concern.