Hello Freddy,
I have asked myself similar questions and actually only see the generator as a sensible solution.
Either you take a small device in the < 1000 watt class with a "socket." That is enough for the heating. Or you take a three-phase diesel generator with >6 kW, then the stove also works. I decided on the latter and had a switch (grid - generator) installed behind the meter during the new construction.