The reason why the Iberian grid is not better connected to France might have something to do with French Nuclear not wanting to be bankrupted by cheap renewables from southern countries, this was the word on the street a ehi'e back, when the push for renewables in Spain in Portugal was starting up.
This is a political problem, having Mitteleuropa depend on power from Putin is apparently OK, but on lazy southerners is verboten. Hopefully this blackout changes that (but I'm not holding my breath).