The article is confusing, but it seems the British Museum (et al) is returning ownership of the artifacts back to Ghana, but they will remain in the museum on loan from Ghana due to a shitty UK law which forbids the museum from actually physically returning them. So now they legally belong to Ghana, who has agreed to continue to display them in the British Museum on on loan status.
It’s a step in the right direction, and it’s currently as much as UK law allows. If/when that law is changed or repealed, Ghana will be free to take them back without any further hindrance.