They probably changed it since I took that old photo in 2016. But I think the Greco-Roman style palace doesn't fit Spain either.
Depending in if you look at South, East or North spain, you need either a Middle Eastern look, a Mediterranean look, or a European look... (actually, a mix of all three with an higher portion of one)
. I was born in SE Spain, therefore I prefer them to use the same assets than Rome(Italy) or Greece, but this may not be the same point of view for someone from the Norther part of the country, which may feel closer to France.
Indeed, if I had to push an specific look for Spain,
Herrerian might be the best choice. Mix of simple-lines buildings alternating brick red, brown stone and white lime, with black-orange-yellow roftops (red brick always with black), in the shape used for mediterranean houses. Red brick/dark roof for the palace, with two peaked roof towers on the sides, and white details and door decorations. I think this one would make a good model - altough not a "royal" palace, i think it is a representative example of the "government" architecture on Spain's peak.