A parallel and necessary step (one that has, suspiciously, suddenly become a culture war for the far right in europe) is electrification of heating with heat pumps, which lets you use your existing gas infrastructure to meet winter generation needs.
I am not arguing against intermittent energy sources but we need to address these problems.
While related insofar some electricity inevitably gets converted back into heating, I don't think its really relevant to this discussion which is explicitly about electricity.
So anything that reduces that heat demand at a lower cost is a relevant fix, this includes heat storage, district heating, general efficiency and insulation improvements etc.
Seasonal storage at competitive prices per megawatt hour is somewhat of a solved problem it just doesn't seem to be getting investment.