Here in Germany we have up to three months of almost zero solar production in winter due to foggy conditions (measured from my own solar inverter). It is not feasible to store summer electricity until winter in batteries. Batteries have self-discharge and would be hilariously expensive per KWh if they only cycle once a year. Chemical storage is probably the way to go here at least, and hydrogen can be used for many other useful things than just heating or running power plants.

Although there are many sunny countries where solar + one or two days of battery storage are probably enough for the full year.

If you've ever played Factorio you'll know that everyone makes batteries because they are cheap, but you also have the option to have a separate power grid that just doesn't get powered at night and shut down your factory at night, which you would do if you modded it so that you couldn't make batteries so easily.

Right, in winter there is less sun. However, there still is some sunlight and in winter you also still got wind energy. Maybe more wind, especially off-shore. Not to mention geothermal and water energy.

In any case, battery storage has been shown to be economically feasible already and are as of now operating at scale. And battery tech is only getting better. The worries about grid stability are therefore unwarranted. If you can manage the up and down of wind and solar, you don't need gas energy to stabilize the grid, you got better bad options and the seasonal variation becomes highly predictable. And of course you could e.g. reserve water potential energy generation for winter times.

And as I said, we also need to cut down our energy consumption. Building data centers to undress celebrities is not the direction of survival.

Hydrogen generation, storage, logistics and electricity conversion are all very lossy. Again battery/solar/wind tech is already there and is only getting better. We should absolutely not use hydrogen for anything, where direct electrification/battery storage is possible. We critically need it for things like steel production, but that's a special use case, where it should be made on-site. Let's be real, the only reason anyone in Germany is pushing for hydrogen is because the German "industry" historically sabotaged local solar and storage tech and now try to salvage their obsolete combustion tech. Hydrogen has a lobby, but no future. For similar reasons Russia and USA are putting propaganda efforts into climate denial: China owns battery and solar tech, China owns the energy future. It's sad, but true. There is no one to blame but those legacy economies being all inert, fat and complacent - they got a million chances to win this slow, slow race, which has been advertised a century ago.