Not sure about the CVR. The communications we are hearing, which leaked, i believe that it is the voice recorder from the ATC and not from the Flight deck. There were 3 persons in cockpit and you don't hear any voices loud and clear from others.
For me, so far, nothing leaked from the plane FDR or CVR. This is all TWR recordings. A pity that liveatc has an outage in SKGR since october.
Asides from this, you are correct. You will notice that on his flight profile, his speed dropped from roughly 200 knots down to 140 knots with a steady sink rate. Continuing the plot, you will realize that he ended exactly where he ended if you don't change something.
But there is a factor.
At the time when the lowered gear, they had the last drop of fuel. A few seconds after this, they don't. There was no more way to raise the gear. As per my knowledge, there is no manual handle to raise a gear.
Unfortunately, not even if we ever get to hear the CVR, we will know why he decided to lower the gear. He was still in decent, around 12nm away from the airport. He confirmed being on localizer but he was not on GS yet. Additionaly I still don't get it why they would need any vectors if previously they confirmed to ATC that they are already descending and on localizer.
And that the pice of ... already left FL210 before the ATC instructed to descend is another bad thing. he took the risk of a collision with the LAN3020 which was flying below him on FL180.
Bad airman ship!