Not a rant, just an advice to anyone choosing free seats:
During booking i picked seat 10A (A321neo) for free. It was the first row behind the "preferred zone" (very front of economy class, marked with a star) that would cost 23€.
Now, two days before the flight, I got moved to 37F, to the very back of the plane. Aircraft type did not change.
The seat that I picked earlier (and in fact the full row) is still available, but is now part of the "preferred zone".
I know, seat selection is not guaranteed, but it just feels so unnecessary. I guess I have now learned to never pick the rows directly behind the preferred zone.