Why are you again putting in my mouth something I haven't said? Are you troll or dumb or what? Could you please take the time and point me to the place, where I have offered as a solution to the OP, to get a 3ph power to his house?
And again and last time, I am clearly stating, that to obtain a 3ph here, you just need a meter change-out, You will NOT pay any extra wiring (except your own side to the 3ph appliance), 3ph power is already and always present at the place of the meter.
Detached houses in central EU do have indeed 3ph power available, and even more often used than just flats, as typical mountain cottages uses 3ph for heating, water pumps and even for cutting firewood. In flats, the 3ph is used sometimes also for heating and for example electric cooking stoves.
Okay, then leave your singlephase in Spain, nobody in central EU could care less. 14kW you say? That would be a nice 3x20A supply in here. That means you (in Spain) have about 2x 16mm square wires. Impressive. We need just 3x 2.5mm square for the same 14kW. You are probably smart enough to figure out, if 3ph power into remote household makes sense, aren't you?
But you can still be an non-believer, as you wish. No wonder that you are stuck with single phase, if people think like you.