This is why it's so ironic seeing everyone arguing about this. There is no way in hell the EU will ever make meaningful reparations. It would be a huge economic hit.
France charged Haiti the equivalent of USD $26 billion dollars (figure from 2017 was $21 billion, so about $26 Billion today), at gunpoint. It took Haiti 122 years to pay it off.
And that's just one colony of many, and like you say, chattel slavery is only one part of historical oppression. Another big player in the EU, Germany, genocided the Namaqua and Herero people in concentration camps. Spain committed all kinds of horrific working-slaves-to-death in silver mines, and so on.
There's no way it will happen. People who are opposed to it shouldn't get so worked up about it.