Your general point is not controversial (sun/wind are unpredictable). By stating that the sun only shines in the summer,though, people are not going to take you seriously and will miss your point.
The obvious solution to the unpredictability of solar/wind is to couple renewable power generation with short/medium term energy storage capacity. There are many ways to do this, all with their own upsides and downsides. E.g. pumped hydro, grid-scale LFP batteries, etc. Also, long-range interconnects to places with more sun and/or wind.
If you inter-connect the whole of Europe you get a pretty stable source of energy with just solar and wind: https://twitter.com/ntsafos/status/1480560060044652546
Now add secondary sources like nuclear, hydro and storage and nothing's impossible.
It does mean keeping good relations with your neighbours, which I think isn't a bad idea anyway.
Synthetic kerosene for making jet fuel or using syngas to make green fertilizer might make sense as a decarbonization strategy but as a means of "storing" electricity it's kind of pointless.